After having a think, you show you`ve a MF 231, I think this has a P3152 engine. Perkins 3 cylinder 152 cu inch. Many of these engines were fitted with a Lucas pre engage starter. If yours is this starter, then sometimes they can be serviced with a few basic tools. Sometimes the solenoid on the top of the starter would burn out, but as yours is clicking, it sounds as the piston is sliding. Attached to the piston is a ring that pushes onto two contacts that send power to the starter motor. These contacts sometimes burn, and sometimes just get dirty. You could just buy a new replacement cap with new contacts. Depending on use, it could be the carbon brushes on the actual starter motor, again these are serviceable. It can be done but you need a big soldering iron. The bottom line is, before you go spending serious money on a new starter, they are pretty easy to repair if you are fairly confident. I think the first thing I would do is connect a volt meter to the small contact on the solenoid, and check when you turn the key to start it shows 12v. If it does, connect the meter to the large wire going from the solenoid to the starter, turn the key and check power is going there. Make sure the battery is good and the connections clean.
Good luck.
