Does anyone know of second hand chldrens clothes stores with a selection for children of 7-8 years. I only seem to find any baby or oddler clothes.

I looked at the yellow pages and got 17 hits, I've past the one near Heuwaage (No. 15 on the list) and I've seen clothes for children there.

Alternatively you may want to cross the border and check prices in Germany and France.