Bosch pump guide, or anyone/garages proficient in Holyhead?

Iv got no power on slight inclined when pulling my 1500kg shed. If I keep the revs low it fairs better than gearing down and using revs, there is no smoke of any description when under load.

I'm hoping that the diaphragm is stuck but having read a brief guide on another forum I dare not go in yet, I know there is a guide on here but can't find it, can anyone enlighten me? Some links to pictures would be good too. Alternatively does anyone know a good diesel specialist in or near Holyhead that will pull it apart ?

Cheer

Sounds like air leak or lift pump to me.

I would check lift pump first as was said-no power on inclines is typical of lift pump failure-injection pump will pull fuel through under its own steam,but not enough when under load