1st check that the alternator is secure to the engine as this provides the ground for the charging circuit and make sure that the engine / gearbox earth strap is secure and the contacts are clean and bright.
if thats OK then check that the small wire that runs from the back of the alternator is in good condition and the connection is clean and bright
as its this that switches the alternator over to charge
thanks matt,i will check those things in the morning.a mate of mine suggested there might be a fuse or a relay blown or faulty?
i will check all those things tomorrow,many thanks,chris.