| would say that you are too early on the specialty plan, it is designed to end the week of your A event. And build should come before that. So that is 16 weeks back from June 9th means you should only really start build at the middle of February, the 11th February I imagine.
Given your holiday I would now do a week of SSB now, a rest week and then start build W/c 28th Jan. Starting it a bit early to offset the holiday. Then Ideally increase the training load of build the two weeks before the holiday. After the holiday I would say it would be a good idea to re do a couple of the build weeks you did before the holiday, rather than just continuing were you left off so that you can build the progression in difficulty in sessions more slowly to compensate for any lost fitness. Would probably be a good idea to add in some sweetspot sessions in the couple of weeks after the holiday just to try to recover some of your muscular endurance that you will lose.
Then just keep going with the rest of your build plan as normal, start the specialty half way through April and do that until the event. that is how I would approach a situation like this.
You have started training earlier than you require so you will have a higher training load over a longer period of time than if you just followed the 28 week cycle, so a longer 3 week deload is not necessarily even a bad thing, not ideal but something that is easy to work around.