It's not the mortgage you would need to change - it's the name on the title deeds, for which you need the mortgage company's permission. The mortgage is just a debt, after all.
If the wife doesn't have enough income to support the mortgage on her own, then the mortgage company will refuse.
In any case, it is highly illegal and the time limit is 5 years:
357. Fraudulent disposal of property
(1) The bankrupt is guilty of an offence if he makes or causes to be made. or has in the period of 5 years ending with the commencement of the bankruptcy made or caused to be made, any gift or transfer of, or any charge on, his property.
Section 352 applies to this offence.
http://www.insolvencyhelpline.co.uk/insolvency -act/p09c6.htm