I think it would be advisable for you to look at the situation in the format of one of the 'Money Makeover' layouts. By renting out your own property, you should probably only count 10 months rent to allow for voids. You will also have to factor in loss of mortgage interest relief, insurance, management fees, letting costs, PRTB registration etc. etc. The return from renting might be a lot less than you think.
Putting rent on top of this would likely leave you very little scope to finance any other loans or to save.
Although living in a one bed apartment with a child is not ideal, it may be better to put up with it for a year or two and maximise your debt reduction or savings to allow you to move on. The alternative is to find a family member with a property with more space than they need and swap residences for a few years.