Based on the answers given here, I have gone ahead and ordered a complete display assembly replacement because the screen has been becoming steadily more unbearable: needing to hold or adjust the screen most of the time just to do anything on the MacBook. And just when I think the thing will stay working and I stop touching everything in the hope of it continuing to work, there come's the exasperating fade-out to white!
Now here's the weird thing... The base had been getting airbubbles in it over some time, and then the rubber really began parting ways from the aluminium. This made the laptop somewhat unstable even when on a solid flat surface. So I have just replaced the base (http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=111215843868).... and somewhat amazingly, the screen has miraculously recovered!! How is that possible? I thought the base was almost cosmetic!
By the way, much as I love iFixit, there screen replacements are very expensive. I made an offer to this seller that was really favourable http://www.ebay.co.uk/itm/130921985376 :-)