Fueling problems - disco 1

[POSBORNE]

I have a 1991, 200tdi H reg discovery 1. the car has completed 215 500 miles. its not a regularily every day go to work car, but used for greenlaning and most weekends to get the fluids running.
Over the last couple of months the car has had issues with fueling issues. It has often refused to start even when there is a full tank of diesel, and the battery is fully charged. It has had a diesel cut off solenoid (replaced 2.5months ago), and last month the diesel lift pump was replaced along with a new fuel filter when the vehicle refused to start again. the same symptons have re-appeared again. the vehicle lights up like usual, tries to tun over but doesn`t fire up. any ideas?

When the garage replaced the lift pump & fuel filter they remarked that the filter was full of crsp (the vehicle had had a service last october with filter change last november for the MOT asn had only done 3500 miles since this failure).

Any ideas what might be know wrong with it? The vehicle has a full tank of diesel.

Thanks

[beast5680]

check the water sedimenter if it has one up under the drivers side rear wing and check the top of the sender in the tank for air leaks its common for them to corrode or the pipes to split allowing air into the diesel line or letting the diesel run back to tank
are your glow plugs working? if they dont the engine can be hard to start as well