DD was in reception last year, they didn't even start on phonics until after October half term.
There is honestly no rush at all. According to letters and sounds the phonics teaching in YR should cover phases 2-4. Phase 2 (19 letters, one sound for each) takes 'up to' 6 weeks of teaching, phase 3 (remaining 7 letters, and one grapheme for each of the remaining sounds e.g. ch, oo) up to 12 weeks, and phase 4 (no 'new' phonics is taught/children practise to read consonant clusters) up to 6 weeks. That is 'up to' (could be less!) 24 weeks altogether; and only really 'up to' 18 weeks of teaching GPCs.
I personally quite like the idea of postponing the start of phonics teaching, and focusing on settling the children into the new environment first.
Also there is a potential problem with powering through the phonics as quickly as possible. What do you do for the rest of the school year? Good schools will find ways to keep up the phonics, I'm sure. But for both my children, the systematic phonics teaching rather abruptly ended around February half-term, to be only taken up again in September of Y1 when they started doing phase 5. In the half-year gap, they did all sorts of things like letter names, alphabet, and memorising 'tricky words'.
My kids (especially DD) also read all the phonics books pink-yellow that the school had and so was given non-phonics books (to bridge the gap until she'd be taught the phase 5 phonics needed for higher level phonics books). So in conjunction with a half-year gap (that's a loooong time for a 4-5 year old) in being taught phonics systematically (or at all), she was also given books that are designed to encourage guessing, using picture clues, etc - and where applying your phonics knowledge won't work, as they are full of words that cannot yet be decoded. So all the good phonics work from the first half year of reception was in danger of being entirely undone.
So, honestly. The teachers only really need to fit in 18 weeks or so, for teaching the initial code of phonics, into the whole school year. There is no rush at all.