103 has been AD for ages. It only gave up its HVMs last year and when I was speaking to the PSAO of 211 Btry last year he said they were re-rolling to provide general support to the RA and they didn't know the ORBAT yet. He was inclined to think the regiment would support UAV ops. Only C Troop, 211 Btry operate Light Guns in the ceremonial role.
I was in 103 RA when they converted in 2001. 211 Bty is a 104 RA Bty, and they're still AD.
The problem with 104 is noone knows what to do with it, 101 have got the UAV gig (2 btys each supporting 32 and 39 in their various roles).
Essentially it boils down to:
HAC: support Special OPs of 4/73 Bty
100 RA: support 7, 29 and 40 (back in 2001 or so they supported 3 Div and wore the 3 Div badge)
101 RA: support 32, 39 and elm 5 (204 (Tyneside Scottish) is a UAV/ ASP Bty, 269 was the CoBRa/ ASP gig, 203 and 205 are still MLRS)
103 RA: support the DAG of 1st AD (3, 4 and 26)
104 RA: ? (supported 12 in Germany, but that has gone to 106, alonng with 12's aligned bty, 210 bty)
105 RA: support the DAG of 3rd MD (1 and 19, they might get the 40 gig with 19 Light Bde)
106 RA: support the cloud punchers (16 (265 Bty) and 47 (457 Bty), plus 12 (210 Bty) as mentioned above)
104 are completely superfluous, their 2 firing btys have no one to support any more, since 22 RA were disbanded back in 2004. A better use might be conversion to another Corps, rather than support a vestigial RA(V) Rgt.