(T) Doblo lucas fuel injection pump and diagnostic

Our garage has done a diagnostic twice and say they injection pump needs replacing costing £2000 = the price of the 2004 cargo van to buy!

We have read several posts here about being warned to check the fuel is not mixed with air bubbles causing trouble with two solenoid/actuators on top of the pump first -which I will definitely tell the mechanic before he starts on replacment- but my question is, if the electronic diagnostics say its the rotar arm inside the pump., is it likely to be a further waste of time and money? Could the diagnostics be misleading?I am also concerned that the mechanic will ignore my findings and go straight for selling me the pump he has already which is not a lucas one and he says should fit. These older non turbo engines seems to have a lot ofissues because the fuel filter is no good for the injection pump. We cant find a cheaper pump anywhere (£700)
Which is my second quesion- anyone know where to get a decent guaranteed secondhand renovated injector pump for a 1.9D non turbo doblo 2004?Thanks for any help appreciated

I have replied to your other post

Email
p@remmington.plus.com

http://www.remmington.info/

The rotors are the only bit that plays up in the Lucas pump as far as the electronics go in them it's fairly simple tbh 2 grand sounds a little steep a recon at a diesel specialist wouldn't be more than probably 5-600