You are now a 'preserved' member of your former employer's section of the RPS. This means that you will no longer accrue further benefits, but that your existing entitlement will simply be uprated by inflation every year until you choose to retire. If you have funds in BRASS they will continue to remain invested as per your preference/decision (and you can change this, just as you could when you were an active member).
You can, if you want, transfer your benefits out to another pension scheme before you retire. The value of your benefits would be converted into a lump sum before being transferred over if you did this. However, you should carefully consider whether this is the right course of action, and it would be highly advisable to obtain professional advice before doing so.