Composing for quintet
Hmmmmmmm! Where to start! Coming from one who's never arranged anything other a xmas carol, I don't really know of any books you might be able to refer to. Since you live in Scotland perhaps you should try liasing with Bryan Allen (Head of Brass, RSAMD and founder member of FABE) as he was known to churn out the odd arrangement for us since the group began all those years ago.
Either that or nick someone else's arrangements!!