Just came across this post! I haven't been saving any of our mail and bills over the past year as this wasn't needed before. Needless to say I have just changed all our settings so that we now receive bills by post.
You should have been saving your mail regardless, because you have always needed it for ILR - because for ILR you need to show that you have received mail at the same address for the DURATION of your spousal visa/FLR(M).
Under the old rules, this was only 2 years, but now that it's 5 years to ILR, I assume you will need to show mail for the entire 5 years... and you MUST have mail from the first year for ILR.
As I've said in other posts, I'm not applying for my second FLR(M) until December 2015....will I be penalized if we don't have mail from the first year of my last visa?
If you can explain and have a good reason why you have no mail addressed to you, then you may be okay.
Do you have ANYTHING at all addressed to each of you from the first year?
Doesn't have to be jointly addressed, and doesn't have to be bills, it can be letters from the NHS, DVLA, HMRC, bank statements, building society statements, phone bills, tenancy agreements etc.
AGH! It's so frustrating - I feel like they are trying to catch you out 
As I said above, this is something you should have been doing anyway, in preparation for ILR... we always advise here to start getting your name on everything and save your mail from the day you arrive in the UK.
So, note to everyone:
As soon as you get your spousal visa and/or FLR(M), save your mail for the entire length of ALL your settlement visas.
