So... there is a change in legislation coming into place that could prevent these developments from happening - 'Agent of Change'. http://musicvenuetrust.com/2017/11/agent-of-change-is-policy-d12-in-london-plan-2018/
To summarise, this means if a music venue is in place before a residential development, the residential development has to be planned in a way that doesn't affect the venue and also carries the responsibility of paying for soundproofing (and vice versa, if a new venue is built near a residential development).
If a proposal design hasn't clearly demonstrated how noise impacts can realistically and fairly be managed and mitigated, it could be rejected by the council entirely.
Although this is a huge success, we still need to make it clear to the developers and the council that this development will only do harm, not just to the venue but the area in general: so please keep signing and sharing so we can demonstrate that this development is not welcome here!