Neil has highlighted some significant info here - I'd say most of us were fooled into believing the airbox cover
Check the ECU ford white sticker (I should have done this eons ago) - my "EEC IV" is EEC V according to that sticker - catch code is 5DAA - this may cancel the belief that some EEC IV ECU's could run thermos - looks like it is only EEC V can.
BBM requires pin 15 - which isn't connected on mine (non BBM), and the red (XH I) or pink (XH II) wire which goes to the ISC and the charcoal canister - these two lines are connected to a vaccuum switched valve (an EF/L one will do) which sits behind the washer bottle in passenger vehicles and has a vaccy line to the BBM valve. Pin 15 can be installed, and the pink or red line runs past the VSV in the engine loom. If my sticker is correct, I could use the existing ECU . . . .

Can other XH owners check their ECU sticker and give us some feedback . . . .

My Grandfathers XH (12/97) has an ED style donk, no BBM..

Not quite snap0964, the Xh ecu does not have the bbm program in it you'd still need one out of a EL gli or xr.

Neil

Ok, thanks Neil - so what you're saying is rather than an EEC IV unit with extra features compared to the EA-D, It is actually an EEC V ECU, with some features (e.g. BBM) not enabled

yes that is correct.

Neil

Yeah, thanks Neil.
Bit of a shame unmodded EL EEC V ECU's weren't fitted to all XH's at factory - would've made for simpler assy I would've thought . . . .