RewriteCond     %{QUERY_STRING} page_id=566842&catid=11
RewriteRule     ^$      /geek-shop-category/?catid=11 [R=301,L]

works

but
RewriteCond     %{QUERY_STRING} page_id=540243&paged=2
RewriteRule     ^$      /gadgets/page/2/ [R=301,L]

rewrites to just '/gadgets/'