JCB 803 hydraulic problem

Hi I’m new to the forum and excavator ownership so please forgive any silly questions. I am trying to bring back to life a 1994 JCB 803. So far I have rebuilt the engine, central joint and a few repairs to the dipper arm. it is running but the action for the dipper and bucket was very slow and the right track was a bit slower than the left. I did the pressure test as per the manual and all is good. I spoke to a reputable parts retailer and the tech guy suggested that it would most likely need a new pump. This is where the trouble has started!!! Went to fit the new pump and unfortunately the hydraulic connections were the incorrect size, turns out someone in the past had fitted a pump from a JCB 801… Thankfully we have a good hydro supplier locally and they managed to source connections for the new pump (which is the correct pump for the serial number of the machine) Spoke to the pump supplier technician again and he told me to wind back the Main relief valves back in case I over pressure the new pump Fired it up after priming the pump and warming up the machine. NOTHING WORKS!! As per the manual I pressure tested the Servo relief and service valves first and they show no pressure at all!.? I tried the rest of them and got the dozer blade and tracking to work but all the digging section does is the boom raises a foot off the floor with a tiny bit of movement on the bucket, and both controllers are inoperable with no swing or slew either on the left. I am at a complete standstill and would appreciated any help..