Where did you get this information from as I've worked there for the past 12years and no they don't, there are some Cat D prisoners who work in the outside farm area but they're bussed in from Hatfield, when it was 2 seperate prisons, Everthorpe did house a few Cat D prisoners who were allowed to work outside on the farm area but that was about 10 years ago.
Cat C prisoners can do work outside of prison , particularly as part of training and resettlement programs designed to help them reintegrate into the community, according to the Prison Reform Trust. These Category C prisons focus on skill development, and prisoners may participate in activities like gardening, farming, or workshops to produce goods for sale. Some prisoners may also be involved in a release on temporary license (ROTL) scheme, allowing them to work in the community under minimal supervision to aid their successful reintegration.
None in this area though, you possible could have quoted one that does this, rather than picking the closest Cat C
I’m not an expert on prisons, I just said Cat C prisoners could be allowed out to work and there was one nearby.