Chain skipping- possible bent hanger

Notable hobbit

I bought a mtb that was in a bad way and im currently trying to get it fixed up and ready to ride but having assembled all the parts the chain started skipping when under load (was fine on the bike maintenance stand). I did a bit of reading around and thought it must be a bend hanger, so I took that off and straightened it. The problem got a lot better but it still skips every now and again.
Is it most likely that the hanger is just very slightly bent and I cant see it or could it be a problem with the derailleur (the cage around the jockey wheels seems to have a little bit of wobble- not sure if thats normal).

I know its not the chain, cassette or chainring as they are all new.

Thanks in advance

cooldad

If you had to straighten it, I'd replace it. Very hard to get it perfectly straight.

The mech cage shouldn't be wobbly.