Thanks for all your helpful replies. I already have a Plat Amex and recently took advantage of the MP GC offer, which I thought was pretty useless due to my limited amount of flying, but it would appear to enable my wife and I to use the T5 lounges when travelling Euro Traveller, instead of sitting in Wetherspoons!

We always use our 2-4-1's in premium classes, so not an issue when travelling long haul.

Re the double avios for transfer of MR points, I haven't seen such an offer for a long time.