You need a letter explaining your work & wages from your employer.
Contact the bank & ask for a letter concerning your mortage. They probably charge for this, but it does look more official.
Get a few quid in the bank first, you need to prove you have 'excess' to support the wife.
You can always blag the bank for a £2000 add-on to your mortgage (for a kitchen rebuild!!!!, and just put it in your account, explain it appearing on your statement as cash you had in your home safe!
In all honesty, you should have;
a) had all this sorted before planning the wedding &
B) Had contact with the IND to ensure you have everyting in order before arranging the wedding. Now it looks as though you've been going behind their back, and they won't be happy.