Mortgage lender pulling out after exchange

I have just exchange contracts last week and are planning to complete in 4 weeks time, though I have heard that the leader will do a bankruptcy check during this period. Though neither my partner - who has very good credit and no debt- and my self have never been bankrupt I do have £5k on credit cards which have piled up since last year and Christmas. On the application I only said I have £3k between us and the AIP was approved and we received the mortgage offer. Is this grounds for the lender to pull out?

Any advice will be greatly appreciated.