if you bought it for £30 then give it a good clean out, it could have been stood for ages and crap solidified in the pipes
I'd fill the machine, then loosen the hose that leads into the pump, see if water flows freely out, then you'll know if the pump is getting a supply or water, then loosen the exit connection of the pump( this end will have a high pressure crimped fitting) wrap a towel round it then turn the pump on, if water spurts out you know the pumps OK.
its just a process of elimination.
The CFR I worked on had a cat pump, which if it is knackered you might just need a seal kit, which you can buy from Cat( search google for 'cat pumps'