EXTENDING MORTGAGE TO PURCHASE BUSINESS

I have a new client who a few years ago increased their mortgage to purchase a business. the previous accountant either refused to claim a prtion of the interest or didn't see the opportunity. It is easy to claim interest in the current year but what about previous years. Is it best to claim previous year's interest in the current tax year with a note in the tax return or write a letter to HMRC with calculations asking to ammend previous tax returns.