So, assuming I decide to try and fix this what do I need? Presumably 2 head gaskets, a set of bolts and then throw it back together? Perhaps some exhaust gaskets too?
What do we think - a Sunday afternoons work, or you'll be lucky to have it done by this time next year?
I suppose the other option is to throw (another) new engine in it, if I can find one.
A head gasket set will include every gasket you need, although some probably could be reused. Yes, you'll need the head bolts. With some shopping around, that's about £100 worth of parts.
Other things to consider whilst its apart:
Thermostat has to come off, and with the timing backing plate off doesn't need to be separated from the transfer tube.
Inspect the oil cooler for obvious external faults.
How soon is the timing belt due? I refitted mine as it had only done about 12k miles in 18months.
DIS pack and plug leads depending on a visual inspection.
New spark plugs. All the engine service parts
Remove, disassemble and clean the breather box.
Front oil seal while the timing belt is off, and a new oil pressure sender
Aux belt pulley.
I replaced all of the exhaust manifold studs and nuts when I had the heads off mine. There wasn't really anything wrong with them, but I've spent far too much time dealing with damaged ones to not spend the fiver on new.
If you have any plans to upgrade to the later exhaust manifolds, now is the time
Flushing the heater matrix is much easier, as is cleaning the filth off the block and heads.