Rover owners: Cylinder Head Gasket Help!

I'm new this so hi everyone!

I bought my 02 reg TF in June and had to get the head gasket done in July. Cost me £780 by a really reputable local garage (not mg specific) skimmed and several parts changed, they told me it would go again but should last about 3 - 4 years.

But nope, overheating again and back to the garage five months on, head gasket's gone again (not back to the same garage as it's closed until after new years so planning on taking it back there when it's open again to see what they say)...

So what can I do?! I'd hate to have to get rid of it, that's the very last thing I want to do but there's no way I can afford to spend 800 quid every five months to have the same parts replaced?! Are there any alternatives and is it my fault this has happened? I avoid driving it at high revs until the oil's warm and it only ever gets to +3000 revs if I'm over 70mph on the motorway... Have I been careless with it or is this inevitable and unresolvable...