hi bibbity, just seen your post on the other thread.
come to bavaria!
If your child likes Playmobil, there is the most FAB Playmobil fun park at Nurnberg. No scary rides, just lots of water to splash in (take swimming costumes), sandpits, giant playmobil, and masses of normal playmobil to play with.
Freshwater lakes are great to swim in, better than the sea, imo. There are loads of lakes further south towards the alps. Almost every town has an open air swimming pool in summer.
the far south east corner of germany is spectacular, brooding mountains and Königsee.
there are thousands of zoos, mines, food factories, schlosses etc that you can take tours of.
walking in the mountains is fantastic.
you could try somewhere around Rosenheim for all of the above.
From the UK, it would take 2 days to drive down here if you go in a leisurely fashion, or 1 day if you shared driving. (I do know an engineer who caught the ferry at about 3 am at Dover, and was at work at midday the same day in Munich, but he probably drives at an average of 200 km/hr.)