Elena Todorova, director of mortgage broker SPF Private Clients

Ms Lovatt-Fraser has to make a fairly quick decision about her home. If she does nothing her mortgage will move on to a variable rate in July, which will be significantly higher. Her lender’s variable rate is 4.24pc, so her monthly payments would rise to £469 from £152. But if she decides to stay until her term expires, she could try to fix for two more years.

If the property is worth £525,000 with an outstanding mortgage of £132,824, selling now could release £392,176. Let’s assume she has £385,000 left after fees. She will need to set aside £24,000 for stamp duty on a £425,000 buy-to-let.

Buying outright would wipe out her cash reserves. Instead, she could raise a small mortgage of £64,000. Rates start at 2.3pc for a five-year fixed rate with a monthly payment of £123.

However, if she needs to buy a property to live in, ideally this would be with cash. This would protect her from sudden rate increases. With a net sum of £385,000 she can put aside a typical 25pc deposit for the buy-to-let, which on a property of £425,000 is £106,250 plus stamp duty, leaving her with £254,750 to buy a new home outright (£250,000 for the property, plus £4,750 stamp duty and legal costs).

With a 25pc deposit, she can then raise a mortgage for the remaining £318,750 on the buy-to-let. Depending on the rental income, rates start at 2.08pc for a five-year fixed rate, with monthly payments of £556.

Her existing buy-to-let mortgage has no early redemption charge. She can potentially raise £234,667 on competitive rates as above, which after repaying her current mortgage would release £58,654. She could use this to boost the purchase price of her new home to £300,000-£308,000 (adjusting the stamp duty accordingly) or reduce the amount she borrows on the new buy-to-let. Her new monthly mortgage payment would be £410 for an interest only mortgage.

From a mortgage perspective it makes sense to sell and buy a new home after her current mortgage expires in July as she is still employed and receives earned income, which may help cover void periods on the rentals. She has only two years remaining on her term, leaving her in a disadvantaged position if the market slumps when she comes to sell. My advice would be to act now.