As noted in this post, the infrastructure and buildings which the Romans left behind gradually fell apart, mostly abandoned and used as sources of building materials for other constructions. However, this Britain Express article Roman villas in England says
The golden age of the villa in England was in the 2nd and 3rd centuries. After that they fell into disuse or were taken over for other purposes.
The article cites no examples of these villas 'taken over for other purposes' and I haven't been able to find any. I think I've seen a picture of church which actually used part of a wall of a villa (i.e. not rebuilt from Roman ruins), but I just can't remember where (and I could be mistaken).
On the continent, Wikipedia says that
the Italian villa system of late Antiquity survived into the early Medieval period in the form of monasteries
and it appears that the same happened in Spain and possibly France.
This article on the villa at Rivenhall in Essex from Historic England says
It has been suggested that the villa building itself may have been reused as an early church or mausoleum.
but this is the closest I have come to finding anything (note the use of 'suggested'in the text above).
Are there any examples of Roman villas in Britain which were taken over and used for another purpose (monastery or otherwise)?
Note: I'm not interested in examples of stones from Roman buildings being taken from the original cite and reused elsewhere as there are numerous such places.