Once I started looking outside London, Rents were very reasonable. Greenwich, where I live was a joke. I have a unit in Medway. 35 from home. Less than a 1/3 of the price of local similar units. I found estates that have practically no tenants, with no deals on offer. All to do with how they finance business units ! The estate I am on, is owned by 2 guys I have met, who have owned it since the 1970's. Most of the tenants I have met and spoken to have been on their for 10 years plus ! Local Police use the site some nights to train Police dogs ! I took to the place straight away !
I may know of an H van for sale here in Dorset, the guy was going to sell gourmet coffee at festivals, he bought 2 vans and spent a fortune getting them re-furbished including the big hatch for serving, Well basically he has split from his wife so they are not pursuing the dream and the vans were for sale. I can ask for you but I doubt if they will be cheap, I can build ovens also, see my other posts. Good luck