I have a couple of the above for sale, £250 no offers, buyer removed (currently located in a building, on the Nottinghamshire/Lincolnshire border).
The boxes are all GB459, which is the standard gearbox as fitted to a Leyland National 2, and also some Tiger and Lynx models. It can be both semi auto and full auto - depends on the 'brain' as fitted to your bus.
If interested, please send a message on here. Thanks