Super Backgammon is a good implementation of the classic board game, published by Digital Precision Ltd.
It includes all of the standard features you would expect, such as the doubling cube. Full instructions appear both on the insert and as help page from within the game.
Advertised features included:
Title: Super Backgammon
Language: SuperBASIC Compiled with SuperCharge, then later compiled with Turbo
Author: Ian Robinson
Publisher: Digital Precision Ltd
Year of Publication: 1985
Platforms Suitable for: All Sinclair QLs and emulators
Commercial Status: Commercial
Price as at April 1985: £15.95
Reviews: QL User (June 1985), QL User (December 1985)
Sources Available from: n/a
Latest Version available from: Unknown