Stringsports based at David Lloyd Anniesland are very professional and Stuart is the guy to speak to for technical advice.
!0% discount if you let them know you are a member at Dowanhill.
Another guy who knows his stuff is Ewan at West End Stringing.
Other options would be Greaves on Gordon Street or Decathlon at Braehead.
Or. If you are feeling adventurous you can string your own racket!! We have a decent manual machine in the clubhouse. Speak to Graham on 07800736202 if you'd like to try it out.