From what I have heard from friends,you should avoid Barclays at all costs. Equity are supposedly more 'user friendly' and are apparently more interested in you clearing your loan so that you can go for more chums in future than the banks that want to take you to 'A-dollar-a-day' sooner rather than later. I haven't taken a loan with them though so I'd advice you ask guys who have. Someone close to you must be servicing an Equity loan.
One more thing,I hope you have done your calculations and what you got justifies taking up a loan to finish up the house as opposed to investing elsewhere and paying rent for a couple of more months/years. Sometimes we are so blinded by the desire to live in our own houses we loose focus of the economic sense. My two Eastern Mau cents.
Never count on making a good sale. Have the purchase price be so attractive that even a mediocre sale gives good returns.