Recreational diving within the UK military is subject to the regulations in BRD 2806 (5), which references BSAC Safe Diving but may include additional requirements so both documents should be referred to.
On the issue of dive computers - The military regulations specify additional information on dive planning when using computers. - When planning dives using a dive computer to monitor and manage a dive, no more than three dives should be carried out in a calendar day. - Before commencing a further sequence of dives a minimum surface interval of 10 hours should be observed. - When multiple dives are being planned, the divers and Sub-Aqua Diving Supervisor must ensure there is an appropriate surface internal between them commensurate with the depth and duration of each dive.