For travel back home you need to look at 'Get You Home Travel in JSP 752 Chap 5 Section 2
The aim of Get You Home (GYH) Travel is to support and improve retention by reducing the impact of separation on Service personnel and, where applicable, their immediate family. It achieves this by assisting Service personnel, who have the opportunity to return to their Qualifying Residence (QRes), with the costs of their travel where the duty unit and the QRes are within the same Theatre. It is paid as a daily rate.
Exemption from SLA charges is detailed in JSP 754 Chapter 9 Section 1 -form what you say you would qaulify for a waiver of charges under sub-para 09.0107n.
n. A Service Person in PStat Cat 5s/c. Married Service personnel or those registered in a civil partnership in PStat Cat 5s/c who are absent from their family home will not pay SLA charges provided their spouse or civil partner is not also living free in Service accommodation at the same time. However, when a Service couple is deployed in operational areas at the same time (for example in Northern Ireland) both individuals will be exempt.
Not that Northern Ireland is an operational area anymore (from 0001 today).
I think that reduced food charges have now been withdrawn with everyone playing the same rate - could be wrong on that though.