Thanks guys.
It isn't turning over at all when it's acting up, just a click noise so what you've suggested may be right.
Started up first time this morning, then spluttered and died, then took about 30 turns on the key before any 'contact' was made :unsure:
Had it at a mechanic who simply...
Well I had this last year - turn key = fek all!
Believed it to be starter motor and it worked after fitting a re-conned one (Thanks Moggy) but problem persisted.
Car would start after maybe a few turns of the key but not always on the first go.
Then had to put in a new battery and it...
http://cgi.ebay.co.uk/Datsun-240z-1972-tax-exempt-240-z_W0QQitemZ290207547349QQihZ019QQcategoryZ122147QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Is this Wyn's car minus the TVR block? Looks like it still got the cream seats?