Hi there Sparkle
From what you have said, I agree with Sean, bankruptcy sounds like the right solution for you. In fact, the rules are that if you are currently living outside the UK but have lived here within the last three years, you can still declare bankruptcy here no problem. You do not have to be living here to do it.
It sounds like both you and your husband would have to declare bankruptcy. To do so, you would have to return to the UK in person and make your application at the High Court in the Strand in London. This sounds very official but actually it is no different than going to any other local county court and in some respects even easier as they are so busy.
I have helped a number of people in your situation do this. I do suggest you speak to an expert to go through everything and all of the implications before you make your decision.
In terms of whether you have a claim for PPI misselling, I can not comment as my expertise lies solely in dealing with debts which people definitely owe. However, in my experience if you do make a claim, it could take a long time to work though. If it takes longer than another 18 months, you will miss your opportunity to declare bankruptcy. As such, my advice would be not to delay on the bankruptcy front and then make a claim later if you feel it is what you want to do.