Thanks Andy..
Do you reckon they will need proof of being together for 16 years or will a marriage contract suffice or are chat logs the norm? (sounds humorous I know)
What about old UK work references etc?
Any supporting document suggestions would be a great help.

When I got married,we posted the banns,bought a ticket,got her passport ILR stamped and that was it.
Sounds like a lot has changed since then.