Non starter

[Tcz6191]

Hi all, I've been a member for a few years but couldn't remember my log in so registered again, I've got a 2001/2 transit motor home with 2.4 duratorq engine, I took it for Mot last week and it passed the MOT with no advisorys but when the tester went to move it after the the test it wouldn't start, they kept on turning it over till the battery's went flat then put it on a jump pack and eventually the starter motor packed up so it was recovered home and I have replaced the starter with a new one but now the starter motor won't turn over however I have put a jumper lead from the battery to the contact on the starter motor and the engine turns over via the key as normal.
So I'm not getting power to the starter via the normal vehicle wiring, I've checked all the fuses and relays "I think" has anyone got any idea what is wrong. I really don't know what to try next. Ps I'm not good with electrics.