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[Lookitt]

My bet would be SH[3705]. This is the front seat heating. It seems F29 provides power to the dashboard seat heating switches S30 and S55. From there there are connections to K183 and K184 which are the front left and front right seat heating controllers.

I had a load of problems with fuse F15 blowing. After much grief it turned out that when some lardy arsed driver moved slightly (over a speed bump for instance) it would somehow short out the seat heating, causing the fuse to blow. In my case it was F15, but both F15 and F29 feed the seat heating controllers so its possible what you are getting is similar.

The simple test is to pull out both dashboard seat heating controls (the knobs). That will disconnect F29 from the seat heating controllers. If F29 then stops blowing then it's fairly conclusive that the heated seats are your issue too.

Even if the heated seats are not on? The F29 fuse problem only occurs if I turn on the air conditioning. If I don't turn on the air conditioning, the fuse never blows. If I put the "ECO" blower on, the fuse does not blow. If I remove "ECO" I switch to air conditioning, fuse F29 blows.

[Lookitt]

You might be onto something, however...

The fans aren't working correctly so there is an issue there that needs addressing 

What makes you say that the fans are not working properly? Because even with the F29 fuse blown they play their cooling role.
I'm sorry, even if you're not going to repeat it for the fourth time as you wrote it, I don't understand how to do the test from the plan you attached, I'm not very knowledgeable on the subject, and the translation of the document.

[LC0112G]

Unfortunatly F29 powers a load of things. The circuits suggest it powers CSR[1329], MK[2206], MK[2305], SH[3708], MCO[3047], IRL[1404] and AB[2649].

CSR[1329] goes to K153 which is the "Relay - Consumer switch-off, time delay"
MK[2206] goes to K26,K52,K67,K60 and P109. These are the coils of the relays to some of the Fans - I think on cars WITHOUT climate control. F29 does not power the fans themselves. It does power the compressor clutch (via K60).
MK[2305] goes to K60, K52, K28, K67 and K22. These are the relays of the coils controlling the Fans - I think on cars WITH climate control. again  F29 does not power the fans themselves. It does power the compressor clutch (via K60).
SH[3708] is the front seat heating dash controls as already explained.
MCO[3047] goes to K149, which is "Control Unit - Minimum Capacity, Engine oil"
IRL[1404] goes to E41 which is "Lamp - Passenger compartment, disconnect delay"
AB[2649] goes to P85 which is "Sensor pad (for Seat Occupied Detection)"

K60 is the relay which controls the AC compressor, so either MK[2206] or MK[2305] are relevant (depending which version of the wiring your car has). K60 does switch F29 power onto the compressor clutch (Y1), so a fault in the compressor clutch can blow F29. I have had a compressor clutch go short circuit before on the LC, and it's basically the same design as the OmegaB. To check if that is the fault, either unplug the compressor connector, or pull out relay K60. 

If the compressor clutch is faulty then you'll either need a complete replacement compressor, or read up on youtube how to replace the compressor clutch on a Harrison V5 compressor. This can be done without removing the compressor from the car, so you don't have to have it de-gassed and re-gassed. New Replacement clutches are about £50 IIRC (from eBay).

[Doctor Gollum]

You might be onto something, however...

The fans aren't working correctly so there is an issue there that needs addressing 

What makes you say that the fans are not working properly? Because even with the F29 fuse blown they play their cooling role.
I'm sorry, even if you're not going to repeat it for the fourth time as you wrote it, I don't understand how to do the test from the plan you attached, I'm not very knowledgeable on the subject, and the translation of the document.

From your description of the fan function, they aren't working correctly. There must be a reason for this.

Switching on the aircon alters how the fans function.

These two things are related. Ergo you need to identify which part isn't working and why.

The fans are self controlled by means of thermoswitches in the radiator. The relays are fed via the fuse that keeps blowing, although the actual power to the fans comes from elsewhere. The only other inputs are from the aircon panel and the engine ECU, although the self contained fan arrangement is pretty efficient at controlling coolant temp.

My availability is limited, but if you can bring the car to Sussex I would be prepared to diagnose it for a fee.

[Lookitt]

Thank you for the details

[Lookitt]

I'm away, and not got access to wiring diagrams.

You can always unplug the compressor (single connector, from memory, underneath it, and see if that stops it blowing.

It looks like you got it right. I unplugged the compressor and cleaned the plug which was full of oil. (engine leak). Looks like the compressor plug is also connected to fuse 29. Maybe there was a bad contact, though I'm not sure if the oil is electrically conductive but I plugged it back in and since 50 km, I no longer have the fuse that blows. I wait a little longer before rejoicing.

[TheBoy]

Fingers cross . Though oil is normally non conductive IIRC?

If it still happens, might be worth unplugging and driving for a couple of hundred km, seeing as it only happens with the A/C on, and you've proven no individual fan motor is causing it.

[Andy B]

..... Though oil is normally non conductive IIRC?

 .....

The loom for the low oil level sensor sits in the sump so oil can't be conductive 

[Lookitt]

Fingers cross . Though oil is normally non conductive IIRC?

If it still happens, might be worth unplugging and driving for a couple of hundred km, seeing as it only happens with the A/C on, and you've proven no individual fan motor is causing it.

Anyway thank you for putting me on this track, I've done 650 km since then and no more problems.

[TheBoy]

Good to hear