Thank you all for your help. You truly are a helpful bunch here. I won't continue to bore you with my problems, but to say I'll keep it running as it is, watch the coolant level over a week or two and see if it drops. I assume that some coolant usage is ok, i mean small minimal amount. If it is a headgasket, I assume the water will disappear pretty quick from the expansion bottle.
I really wanted a Gti for ages. I bought this for £1600 and if it runs for 12 months, don't mind spending money on it.
If it is the HG, can I pretty much trust any garage on the work? A garage has quoted me £595 cash to do a HG replacement. Is that about right? Does anybody recommend a place or would anybody here like to do it for me and I pay them? Sorry for the direct question, but couldn't think of another way to put it.
Thanks again