First & foremost, your solicitor should have put your lender to 'strict proof of any debt' and 'no arrears are admitted' - has this been done ?(posted 8018 days ago)Secondly, has he sought to rely on Norgran -v- Cheltenham & Gloucester Court of Appeal 1996 ? Where it was held that the remainder of the mortgage term was the appropriate starting point for the repayment period of any arrears - which from your posting you can more than satisfy on the figures proposed.
The County Court is bound by this precedent. Has this been pleaded for you ?
Good Luck ! Vic