Originally Posted by
Danusa86
Is it worth visiting any of the lounges at London T3 and accept the "less convenient" layover in London rather than Madrid considering the better lounges?
Stay clear of the T3 BA lounge.
My personal favourite is the CX lounge at LHR T3: Nice view of the tarmac and better food offering than the BA lounge. YMMV. But hey you can test the BA, CX, AA and QF lounges and decide for yourself.
That said, apart from a very few exception, I would never make a more complicated detour to visit a lounge.