Very slow starting Bedford Turbo lorry - local yokel
I have a Bedford Turbo horse lorry. B reg, SH suggests it has been cared for.

It runs no more than once a week, sometimes less, and is very slow to start. It has a new 95Ah battery but that does not have enough reserve to run the starter for the time it takes, so I have an older but serviceable 110 Ah battery that I charge and connect using jump leads. With this set up I can always get it started, but after a very large number of turns.

What should I suspect? My first guess is the injector pump.
Very slow starting Bedford Turbo lorry - defender
1 are you sure its not a bad battery connection and by using jump leads you are bypassing the problem
2 lazy starter motor or drawing too much power
3 very small air leak allowing fuel to leak back to tank
4 lift pump fault or gauze in lift pump neading cleaned
5 when were the fuel filters last changed and the water trap cleaned
Very slow starting Bedford Turbo lorry - Cliff Pope
Faulty glow plugs, if it has them? A diesel will start without all or some, but it take a lot of turning to generate enough compression heat.
Very slow starting Bedford Turbo lorry - Number_Cruncher
I strongly suspect Defender is right with No 3 on his list.

Its very easy to check out, if you can access* the hand priming lever on the lift pump, give this a large number (100 or so, to be sure) of strokes prior to trying starting. If the engine then starts straight off, then you need to find and cure the leak. The lift pump itself is a good starting point in this hunt, followed by the fuel filter seals.

* If it's a TL, then you'll probably need to put the cab up. If it's a TK, just hope the priming lever is towards the back of the engine!

Number_Cruncher