is my starter motor burgered or is it something else,,its a 300tdi auto and every now and again when i turn the key it fires straight away and now and again its like theres a machine gun going off,could it be the solenoid or the starter?

it could be the solonoid on the starter but could also be a faulty earth connection or you may have worn brushes in the starter motor.

If you can take the starter off and get it to Sheffield there's a firm called Chapmans near Shalesmore that will check it and replace the necessary bits. They are quick and very resonably priced.
Nothing fancy, just the bits that are needed. I've used them for many years and they're great, much cheaper than buying recons which tend to have a short warranty.
Hope this helps.
Paul.