BtL mortgage for Lasting Power of Attorney - Help please

[alfienumeric]

I need to remortgage my father's property under the terms and conditions of his Northern Rock Lifetime mortgage as he has just entered full time nursing care. I have a Lasting Power of Attorney that has been fully registered with the Office of the Public Guardian and I thought this would allow me to act as if I was him.

Rather than sell the property and invest the money for my father I want to remortgage it to a Buy-to-Let mortgage with no ERCs. This is because I have a formal letter from a developer offering more than �200k over the current market value. The offer letter from the developer is genuine as the site will be developed as sheltered retirement homes and a care home and is not therefore affected by current market uncertainties.

Unfortunately my Dad is 78 now and suffereing from Alzheimer's so cannot sign anything for himself so I need to exercise my power as attorney and protect his interests and the interest of the estate. If I buy the property from him I would have to buy below market value as I don't have sufficient to fund it myself but this would, I feel, breach the LPA as the subsequent increase in value would become mine and not be available for the other beneficiaries on his death.
Therefore I'm hoping someone has experienced a similar situation and can point me towards a sympathetic lender.

There's also a slight added complication in that shortly before dad went into care he got into difficulty with his credit cards and some are approaching default status. I have been making regular payments but his bank refused to let me know details of his account status until the LPA was in force and the OPG's service standards are six months. So, even though I started the whole registration process in March 2008, I have only just got confirmation from the OPG that the LPA will become effective from 8 September 2008.