
The Dangerous Dogs Act was enacted in 1990, and the breeding and importaion of Pitbulls, Japanese tosa's and fila Brasiliero's was banned, and any dog of the 'Pit bull Type'
Those dopgs that were in UK at the time were required to be Registered, Microchipped, Tattooed, Nutered and Insured, and be kept muzzled and on a lead in public.
This means there should be no Pitbulls alive in the UK less than 14 years of age.
There are those who have importyed these dogs ileagally, or as you say are breeding and selling cossbreeds to look 'of the type' to gullible folk who seem to feel the need to own an ilegal dog. So yes the dog could be seized and destroyed as many have been over the years.