No power when starting with hot engine

I have a 200tdi 110 defender with the following problem.
If the engine is switched off after reaching temperature. It invariably restarts with very little power and eventually stops. The only thing that gets it going is bleeding air out of fuel system (bleed screw on filter and pump with fuel lift lever). I’ve checked all the fuel system connections and all appear to be air tight. Any ideas what could be happening? When it is going it can go for hours without any issues. Only happens when hot engine is restarted.
Thanks LGD.

welcome by the way!!:welcome2: id look at y its getting air in the system? may be lift pump or even the seal on ur fuel filler cap or the chassis may have pinched a fuel line. or try the filter in the top of the lift pump...sounds like your fuel is running back to the tank. try also bleeding it from the injectors rather then filter screw