The animals will be allowed on Longis Beach between 17:00 and 08:00 from Monday until 15 September.
Kent Police appeal for witnesses or anyone with CCTV or dashcam footage of the theft to come forward.
The Doc Martin and Wuthering Heights actor says being with heavy horses is "a bit of soul food".
A mounted training day is held to prepare police more effectively for public order incidents.
Spirit Dancer had a long career but he is now enjoying beach walks and beer for dinner.
Geoffrey Williams said his method was used to "break in ponies" but accepted training had moved on.
The Isle of Man's chief vet warns owners to be vigilant after a rise in UK cases of the disease.
The charity uses sessions with horses to help ex-service personnel deal with mental health issues.
The infrastructure minister says a financial case is being amended after feedback from the treasury.
