you could be right mike. or they could construe filming of the lap to be timing it, and then it could be seen as racing. racing on a public road is illegal, both in UK and Germany.

not saying i agree with it, but it's better not to risk it

as for other things to do in the area...

the kart track is a lot of fun in a group and is a reasonable price. if the weather is dodgy, consider booking up in advance for later that day or evening.

if you want something other than driving, the Mosel valley is not far away and is absolutely spectacular. it's famous for it's wine, and there are any number of small wine producers who will be happy to let you taste their products and view their cellars or production.

not too far away is cologne which is a beuatiful city on the rhine. the cathedral is magnificent, and the old town by the riverside is lovely and full of bars/cafes/pubs. also in cologne is plenty of adult entertainment, including the famous pascha club/brothel. brothels are both safe and legal in germany.

near cologne is an amusement park.

the beautiful country of luxembourg is not too far away and should be worth a visit.

the town of bitburg is not too far away, famous for it's beer.

all depends how long you will be there, and what you like doing.