I've seen this written in dirt on a few lorries whilst driving to and from my folks over Christmas and have no idea what it means....
any ideas?

Here u go .... according to

http://www.theanswerbank.co.uk/DisplayAnswers.go?question_id=37640&category_id=12&index=13

"its a phrase used by Alex Lester on his Radio 2 show between 3.00 and 6.00 AM , believe it is about slapping someones head"

Makes sense.

Loooaaaadsa truckers listen to Radio 2.

If you ever listen to the travel info, it is usually phoned in by `18 Wheeler Wallace` etc.

well done blokes :thumbsup:
the wonder of the t'internet :cool: