Aircon issues on a 17 year old car? Who'd've thunk it...
As for coolant leak showing on the sump, had you listened to the advice given when your garage charged you for wrong headgasket diagnosis, then your thermostat housing would have been fixed
Could also be leaking from the waterpump btw.
Complete exhaust is less than £100.
Was considering WIM for my next set up once the suspension work is done, but partly depends on whether I do kit here, or curry tokens are involved. By their nature, it's prudent, but expensive, to renew the suspension in one hit rather than getting it set up again at £60-100 a go everytime summat gets replaced. Mine will be nearly £900 when done using mostly quality parts (wishbones are cheapies, but alot of poly going in too - not the front vertical bush though
), could be done for around £450-500 if not fussy about parts.
And yours is at the mileage where everything starts to wear out... 80-120k is the expensive time for an Omega