B&H in New York have Lightroom 3 on sale for $70 US (about 45 GBP). Shipping will cost, at the cheapest, another 30 GBP, but still a good deal.
http://www.bhphotovideo.com/c/produc..._Software.html
It ends sometime today (Feb 15).
I suspect others will be doing the same soon to clear stock. Adorama also has/had it on sale for $80 US.