Michael Bell may step Heartbreaker up markedly in class for the Park Hill Fillies’ Stakes at Doncaster.

The Newmarket trainer is considering Thursday’s Group Two over the St Leger course and distance for the progressive daughter of Cable Bay.

However, he has also given her an alternative entry in the Weatherbys Bloodstock Pro Persian Punch Conditions Stakes at Salisbury the following day.

Bell has been impressed by the four-year-old’s improvement in such a short time – because she was a late starter, making a winning debut in a bumper at Fakenham in March.

After then being well beaten in a Grade Two bumper at Aintree in April, Heartbreaker was not seen out again until the end of July when she got off the mark over hurdles.

Bell has since switched her to the Flat, and she was again successful at her first attempt when taking a novice auction event at Wolverhampton by seven lengths – after which she was bought privately by King Power Racing

“She could go to Doncaster, but she’s also got an entry in the Persian Punch Stakes at Salisbury,” said Bell.

“We’ll have a look at the entries for both, and then take a view.

“She’s come a long way in the last six months.”

Bell also has high hopes for Improvise, who opened her account on her second start at Haydock on Friday.

The two-year-old, owned by the Queen, benefited greatly from her racecourse bow at Newmarket last month to land a battling head success over a mile.

“She’s a nice filly going forward,” said Bell.

“She’s very similar to her mother, Set To Music, and hopefully she’ll make into a nice middle-distance filly.

“She had a real good blow after Newmarket. I think she went there quite under-cooked in hindsight, and she’s come on a lot.

“There are no immediate plans for her.”