TartanCladPB: I'm not sure I understand the problem you are having making the adjustment (ie shortening the chains to raise the sporran), but try the following:

Assuming the hooks are attached to the D rings behind the sporran, remove each hook from its D ring. Now, on each side of the sporran run the entire hook through its D ring and attach it to a link higher up the chain. That will effectively shorten the chain on each side. Just find the link that acheives the right height and you're done!

Sorry if I missed the forest for the trees.