We have just returned from a holiday in Dorset. Whilst at Bowleaze Cove I found this, which looks like a fossil dog footprint. Is it? It was about the size of a large dog's print and was in a huge rock on the shore so it's still there! Thanks
...But nothing that would leave a footprint like yours.
The arrangement of three 'toes' within the obvious paw shape - that's also difficult to equate to a particular group of animals. The rocks at your locality are much too old for cats (see this discussion).
I think your specimen is merely a footprint look-alike, unfortunately.
Probably, the 'toes' are where small pebbles, that had been embedded in the rock, have fallen out. However, there is a certain similarity between them, and similarity of gap between them - and that does bother me a bit.
I can't think of another explanation.
So I would be pleased to have somebody else's opinion.