Not a TRA as such, but it's worth noting that the roundabout itself falls within the scope of the future Elephant & Walworth Neighbourhood Plan, whose proposed boundaries will soon be the subject of public consultation
I'll second that search for a neighbourhood group for brick layers arms area (OKR end). Ive emailed southwark council before (address listed on the southwark consultation saying contact us if you want to get involved)) and asked to be informed of groups and any future consultations regarding the area. Never received a single notification and cant find anyone who knows about which group we wodl come under.
Bricklayers Arms is one of those awkward spots that's on the boundary of lots of different things.
For instance, three local government wards meet at the junction (Grange, Chaucer and East Walworth) and so the area is split between Borough, Bankside & Walworth Community Council and Bermondsey & Rotherhithe Community Council.
I too live in Searles Road and used to attend the meetings of BATRA but do not have any contact details now. I think the Safe Neighbourhood Police team sometimes attend these meetings too and it may be that they can give you a contact telephone number. Hope this helps.
I think the three of you together should set up a group and see where it goes from there, I bet there are other's who would want to be part of it and who are just waiting for someone to take the first step.