Cheers wammers, I will have a go, with another flush after I get back from holiday.
Going down to shell island wales for a week and the weather will mean I am out driving if it rains! Few 100 miles might sort it out.
Incidentally no clunking today, smooth through the gears, you are right perhaps it needs time. Just got another bottle of the Lucas oil anyway. Will give it a try in a couple of weeks if it ain't sorted ny then.