When my wife (UK citizen) and I (US citizen) were looking for a mortgage before I had ILR, the banks we dealt with in England said they'd be happy to give her a mortgage without me on it if she made enough money to qualify for the amount we needed. She didn't, so we waited until I had ILR.
I don't know if much has changed, or if the situation in Scotland is any different, but my guess is if the mortgage is going to be in your husband's name only, it wouldn't matter what your visa status is, but if you want to both be on it, you'd need to have ILR.
I think a few people have used mortgage brokers to find mortgage companies who were willing to deal with people on their pre-ILR visas, so you might check into that.