It does seem variable, but you can book online without being invited to now if eligible. I have heard nothing from NHS but am booked in for exactly 182 days after my second jab. I've heard nothing from my GPs throughout this - other than a text saying not to contact them and ask about the boosters.
Good to hear, but we are really playing catch up.
I became eligible for my booster a few weeks ago and could even book until a few days after the eligibility period started. The earliest I could get my booster was one week after I became eligible.
While this might sound trivial, moving everything forward by a week can help the overall position markedly as immunity is really beginning to wane as we get to 6 months so any additional days of waiting is additional time for someone to catch, spread the virus and for either of those people to get ill, long covid etc.
I really don't understand how they managed to take their eye off the ball so badly with boosters, and with 12-15 year old, having been pretty hot off the mark back in the early part of the year with first/second jabs.