hi mycroscope, the Hiscox Legacy Gad case is what we use and it's a good fit, very snug. Their standard "off the shelf" case is the Pro-GAD but you need to phone them and request a Legacy GAD instead.
Hiscox Cases Limited
Units 5-8, Mill Park Industrial Estate, Hawks Green Lane,
Cannock, Staffordshire WS11 7XT, UK.
Phone: +44 (0)1543 571420
Fax: +44 (0)1543 571458
They are very reasonably priced for a hard shell case.