Reillo RDB1 boiler (kerosene burning)?

Hi. My boiler is on the blink.
Recent History is that 1) it ran out of oil and got airlocked. 2) fixed airlock by bleeding through the pressure gauge port (wrong place I know) and got boiler going. Ran for a week and then locked out again 3) Noted water leaks leaking water on top of air supply siphon thingy so replaced safety valve and pipes in water circulation. 4) Noted a little oil leak in supply pipe - fixed 5) Still fails to restart, I have bled again through supply guage port this time.

I think the pump is failing to build up the required head of pressure. When I go through the restart sequence with the pressure gauge port open oil flows out under gravity pressure until pump kicks in, then the flow stops completely - I think it should come out under 4 Bars pressure at this point.

Any help appreciated.