If you're talking about the actual Trent at Winthorpe, Ashfield now own the Trent around the back of Winthorpe Lake, which is also theirs. I think Worksop and District have the Trent just downstream from the Winthorpe stretch, and A1 pits own the opposite bank.
Newark Dyke starts at Staythorpe, runs past the weir (Bob's Island), past Newark Castle, to the weir at/near the junction of the railway lines, and then rejoins the old trent (as stated) at Crankley point. Some sections are private clubs, others day ticket. Long time since I fished it but the Newark stretch towards Farndon used to be very good for roach fishing.
Roughly halfway between Winthorpe A1 road bridge and Crankley point is an outfall. Fish a stick low side of this for a good mixed bag. Feed hemp and casters and fish bronze maggots on the hook. Enjoy. ?