Not sure the MOT has any part to play TBH.
Perhaps if it's a permanent/fixed alteration to the vehicle? :-/
I'd assume the 'auxiliary' tank would be plastic and secured to the boot floor
However, this cuts down on the space available for storage which may be an issue on such a long journey.
Insurance wise.... same tbh. You haven't done anything to alter the cost, vulnerability for theft, location it is parked etc etc etc. I don't see why they should need to know either
He would however have altered the original equipment spec of the vehicle and would be obliged to notify his insurance company of this. If he didn't, and needed to submit a claim, it's quite possible that the claim would be disallowed because of this failure to notify.
In many cases people don't report changes of or alterations to the original specification of the insured vehicle and become aware - when it's too late - of the short-sighted nature of their actions when the insurance company challenges the claim.
Q15: What about converting an existing vehicle which is already registered?
A: It depends on the category of vehicle and how extensive the modification. For cars and light trucks, the Driver and Vehicle Licensing Agency (DVLA) should be notified and they may require an inspection of the vehicle depending on the extent of the modifications.
From: http://www.dft.gov.uk/pgr/roads/vehicles/sectionecwholevehicletype/faqs?page=1
The fuel System
Has no leaks and the fuel cap fastens and seals securely. The fuel cap will need to be opened so be sure the key is available.
From: http://www.direct.gov.uk/en/Motoring/OwningAVehicle/Mot/DG_4022109
To comply with this I would suggest that the tester would have to be notified of the alterations so that the integrity of the additional tank and the means by which fuel is added to it, and sealed, could be examined.
The additional weight of the tank and fuel may also cause stability problems and cause unintentional wear on the standard suspension components.
I cant be arsed separating the quotes, but.
Car was supplied as new with Firestone/Pirelli/Goodyear Tyres...... I choose to put a different make on..... Do I have to inform my insurance company? NO. Yet I am changing the original specification of the vehicle. OH NOEZ!
The original head unit is rubbish, it gives poor quality sound, can I change it. Yes I can. Shall I tell my insurance company? Nopers. Why? Because they dont need to know, even though I'm changing the original specification of the car. They wont pay for the replacement of the head unit, granted.
I picked my car up FROM NEW at the local Vx Dealership. I cant drive it anywhere otherwise it will use fuel, thus rendering it different from when I picked it up. (Sorry Sir, I cant pay out on your claim because you have used petrol and your car is dirty).
Why does everyone make insurance companies out to be evil? The two experiences I have had, have been amazing. They have looked after me and made sure I got what I was entitled to, and more.
NB: A Fuel filler cap doesn't need to be locked, just securely fitted. Any moron and their cousin knows that![/quote]
Thank you for your considered reply BM.

Car was supplied as new with Firestone/Pirelli/Goodyear Tyres...... I choose to put a different make on
Is that a valid point? I would imagine that you would be obliged to replace the tyres with ones of a similar specification - not necessarily make. If you fitted tires of a different size on the same axle or mixed the types between cross-ply and radial or had tyres of a lower than recommended speed rating, you may well have problems with insurance as well as Construction and Use Regulations.
They wont pay for the replacement of the head unit, granted.
This point illustrates very well what happens when the insurance company is not informed of changes.
I picked my car up FROM NEW at the local Vx Dealership. I cant drive it anywhere otherwise it will use fuel, thus rendering it different from when I picked it up.
In relation to the specific points made regarding the proposed installation by Stu surely this can't be a serious point?
Why does everyone make insurance companies out to be evil?
I can't see how you're suggesting that I was making insurance companies out to be evil. I most certainly was not. Insurance companies are in the business of making money by lessening risk - they do this in many ways one of which is contesting claims in these circumstances. (Quite rightly in my view)
NB: A Fuel filler cap doesn't need to be locked, just securely fitted. Any moron and their cousin knows that!
Well BM I'm far from being a moron and I don't have any cousins so I fail to see where the relevance of the locking element of your point comes into play. The instructions given to the MOT testers simply relate to ensuring that the means of filling the tank is topped by a securely fitting and well sealed cap – which, if it were of the locking variety, a key should be at hand - quite sensibly.
I'm disappointed that you chose to reply in this way BM which I feel to quite off-hand. Was the tone of my posts or the style of writing unsatisfactory?
I was simply making what I considered to be valid points to Stu in response to his question - obviously you thought differently
