Pheeeeeew! thanks for that. We actually got "married" in pakistan in Nov 08 but her settlement visa was refused on the grounds that i hadn't divorced my first wife properly so my marriage last year was not recognized by UK law...i have now obtained a UK divorce so will have to marry my wife again. As we cannot marry again in Pakistan (our marriage there is already valid), i will apply to bring her over on a fiancee settlement visa and then have a quick registry office marriage here so that UK law recognizes our marriage.
Your marriage to your present wife was not accepted at the time of her application ,because you didnt provide sufficient and legal document to say your previous marriage was null and void.
Now that you have got that ,they should accept your latest marriage as valid, because it was carried in accordance with Pakistan law ( which the UK accepts). You dont need to get married again in pakistan, because as you say your marriage is registered.
I think you are going to have problem bringing your "wife" as a fiancee ,now that the BHC in islamabad has a record that you are married, because she is not your fiaincee is she?. she's your wife.
The marraige carried out in Pakistan is valid, and it will be accepted as valid,and therefore it is not a legal requirement that you have to get married again in the Uk to have your marraige recognised.