Unmarried Partner....need help urgent

I am 33 I was married 10 years ago for about 1 month. We split up but never got a divorce. My girlfriend now has a british passport and we would like to move to the UK. If I omit this becuase I don't have a divorce certificate will UK immegration find out? Will I be band from the uk? Do they look that hard? Please help!

yes , Uk immigration could possibly found out that you are still married, you should start the divorce procedure as soon as possible.
If you provide (or hide) information they would probably ban you for a certain period of time.

If I show them I started to get a divorce with court documents(I have filed) but dont have a divorce can i get clearance? or must I have a full divorce first? Has anyone gone through this before?

they will ask to see the final divorce papers

is a letter from the landlord stating we lived together enough or do i need rent receipts?

you will need at least 3-4 different type of bills with your name and her name (with the same address) on it showing at different dates (from the start to to end of the 2 years you have been living together)

It can also be bank statements (as long as it shows the address) and wage slips