hi the machinist here's a little info for you. In my experience most insitu machining companies are always looking for the right people they don't advertise their jobs much. different companies do different jobs allot do things like pipe cutting, flange facing, drilling,tapping,milling,boring,bolt tension,leak sealing that type of work.Then theirs the really specialised companies (not many) who do very precision work like crankshaft machining and orbital machining. if you have done an apprenticeship and have a good machining background you should be able to find a company not sure if their are any in derby but their are in the midlands good luck.