I'm not far from High Wycombe
A great dummy tip is to try popping it in the mouth then lightly tapping it. Sounds daft but really works (not every time but like, 3-4/5 times). Just quick little two-finger "drumming" taps.
As for getting LO onto a bottle, you need to be WAY out the way. Like, out the house out of the way. LO will smell you and your milk and clamour for that if you're anywhere in the building. They can smell FAR.
Get dad or grandparent/friend/whoever to offer the bottle.
Hold LO the same way (as much as possible) as you hold them to breastfeed so they still feel secure.
Offer the bottle an hour or so after a breastfeed. Waiting until they're starving and trying to force it on them will only stress them out.
If they refuse it, don't push. Try again after the next feed, and so on.
Cross fingers and pray xx