It's been 6 weeks since my last post here, so I hope this isn't classed as a double post.
Just to update people that, over the last couple of days, the online of FM5, FM6 and FH2 seems to be very intermittent but it's not down fully like it was before.
I was able to access messages and download 2.4m credits from Forza Rewards which appeared as one single gift message on each one. That enabled me to buy the Shelby Cobra in FM5 which I need for the "beat a Ferrari" achievement, and a couple of hypercars in FH2 (I only have 11 cars left to buy in that game now, but the top 3 are around 5m each, so realistically I'm just aiming to pick up the other 8 outstanding cars for "completion").