hi martin.

with regards to the car loan. It will depend on your income offset to outstanding debts. It should not directly affect your mortgage or the amount to be borrowed. (this goes mainly on your income). If anything it will affect your credit report. Lenders (not all) are becoming more adverse to offering loans to people with large payements. It will depend on the requirements of the lender. However so long as your payments are up to date and on time it should not pose much of a problem.

you can get your credit report from experin. This will allow you to see what the lenders see so you can get an idea. For a fee you can get your credit score from experian too.

with regards to the purchase deal.. that again will depend on the sellers requirements. some offer to pay the deposit. However it is worth bearing in mind that no deal is final. House builders/sellers are in a bad situation at the moment so it is worth negotiating a deal. They may pay the deposit even if it is not in the initial deal. Thiese are arduous times so people are willing to make deals.