Yep - 2-4 weeks is pretty well the norm, tho my Onc said it could be longer if I wanted my holiday to Norfolk Island BEFORE I started (4-6 weeks later!) I opted for Rads first, then 2 weeks after that, my holiday, so I could enjoy it, knowing rads was over! :)
Enjoy your break, @Frances54 - keep lathering up with the lotions, as the warmth continues for the next 3-4 weeks so vital to keep the moisture up to it. If you see any extreme redness or the skin breaks down - make sure you ring your breast care nurse or the nurses at the radiology Dept for advice or get it checked out.
All the best xxx