Now I've read that I can apply from 28 days before my 2 years here (May 2014) and I've read I can't apply until 28 days before my expiry of my FLR-M.
Which is it? I'd much rather apply right now, but I dont want to lose £1500 doing it!
It's 28 days before your FLR(M) expires... so 28 days before February 28th 2015.
Basically, it depends on what visa you had when you entered the UK - you have to spend 2 years in the UK on a spousal status visa (spousal visa or FLR(M)). You were not on a spousal visa when you entered and your time on a fiance visa does NOT count towards the 2 years for ILR.
So, in your case your 2 years to ILR started on the date your FLR(M) was issued and ends on the date it expires... because FLR(M) is only valid for the 24 months you need to qualify for ILR.
If however, you had married in the US and entered the UK on a spousal visa, it would have been valid for 27 months, giving you 3 months leeway to enter the UK and still qualify for ILR before it expired. So, your 2 years to ILR would have started on the date you entered the UK on the spousal visa, and you would therefore qualify for ILR 28 days before the 2-year anniversary of arriving.