Right, here's what you need, heres what you get...
Donor car, you want to be a 130spec XR3i / Orion Si 130 / Fiesta RS1800. And you'll need a 105spec flywheel, clutch to suit spec.
OR any 1800 fiesta or escort, ghia, LX, etc. You can buy 130 spec cams, TB and ecu if you want to upgrade. might be cheaper this way, if having trouble finding 130spec to start with.
If going 2 litre. 2 litre bare engine, injectors, TB, pre PATS ecu and full car loom.
1.8 escort or fiesta sump, waterpump, gearbox sandwich plate thing, over the top "efi" inlet - not that plastic shit, 105 spec flywheel, clutch to fit spec, some water pipes. Probly best to use a donor car from the above list just minus engine and injectors, loom and ecu which you could sell on as a package for 1.8 conversions....
Little bits and bobs including custom length alt belt, mini fuse box for lambda, ecu, coilpack... hose reducers and T-peice, solder, heatshrink, tape, Welding wire cutting disk, K&N cos you can't fit airbox. etc etc
You need to cut the downpipe just pre cat, make it fit your existing system, possibly make another hanger to keep it tight to the car as I have done on mine since ford fair 2006
You use a mixture of the donor car and the receiver car's water pipes, build a fully enclosed engine management loom, hook it up to live, switched live, earth, rev counter (efi clocks), water temp guage sender needs earthing/swapping.
Refabricate the top engine mount using CVH item.
Either the 130spec 1.8 or the 2.0 when fitted, with K&N, less cat, less EGR should make around 145 bhp. 1.8 is a bit more straightforward conversion and revs really nice too. I wouldn't do the 2litre for the same price.
Besides from the labour, you're getting consumables, an oil change, custom length alt belt (that took ages to find the right one in the first place), and most importantly you know it's gona run. Well worth 500 quid IMO! You could and probably would spend weeks on it yourself if you've never done similar before. Cos it is a conversion, there are different ways and different approaches to some of the steps, you want someone who has done it before, and has a proven method.
My mate's got a unit on our local ind estate, if you're still uhming and ahhing in a couple of weeks - I'm not far from you, just bring it and I'll do it.