Chrissa
I seem to recall from one of your earlier posts that one (or is it both?) of these properties is in negative equity. In other words, it is not just a case of you being behind with the payments on the mortgages. If it/they is/are in negative equity it is quite possible that the mortgage lender will not agree to a sale because their debt would not be paid off in full by the sale proceeds. (I know this sounds daft because repossession normally results in them getting less for the property, but it is certainly the way some lenders act.)
So before you try to sell make sure the lender is going to agree to allow it.
As has been said, you need to get your tenancy for the cottage wrapped up before your credit rating is adversely affected by mortgage debts. However, it may be that you already have a bad credit record from the arrears & that could make it difficult for you to rent if a credit check is done, unless there is someone who could act as a guarantor.
I think you are likely to get more detailed (& hopefully free) advice from the Debt Agency you have consulted than from seeing a solicitor, which will cost you & many (perhaps most) solicitors are not really in to detailed knowledge of debt related matters.
If you do end up with a lot of mortgage related debt & no prospect of paying it off bankruptcy may be worth considering. The Debt Agency would be able to advise you on this.