Just an update. I successfully changed the upper and lower seals on the fuel injection pump. It is tricky getting the adjuster back in the hole on the shaft, but it finally went in. Pump was marked to enable correct alignment and to hopefully maintain correct quantity adjustment. Good instructional video on ytube about priming pump after and replacing seals.
So back together and restarted. Only problem is a rough idle at 800 tickover. Unsure if air in lines. I would like to crack fuel lines to expel any air but they are welded solid at the moment. Have left soaking in wd40.
Any advice on moving the nuts appreciated.