Solidworks user here. Have used both inventor and Solidedge in the past. But have stuck with Solidworks for the past 10 years. I think you’ll get a seat for under £5k.
There probably isn’t that much between the Inventor, Solidworks and Solidedge, but Solidworks has the largest user base and you’ll find the most help on line. For instance I’ve had to model in a way I am not very proficient in over the past week and was getting quite stuck. Some quick on line research has found the answers to each problem I’ve encountered. Invaluable I think.
If you go with Solidworks, it would be good to know how much you pick up a seat for at the moment.
Also I second working in 3D, even for simple parts. Then creating 2D drawings from that.