I'm trying to remove surface mounted wires in the hall (1905 single
skin brick built house, limited trunking opportunities available,
don't ask!) so the wired doorbell is coming out.

However, SWMBO likes the very loud traditional ringer that the
existing one has. It is powered from a transformer which outputs 8V /
1A. Is there likely to be any product which would allow me to convert
the existing bell into a wireless doorbell system? Presumably a bog
standard 9V battery would ring the bell sufficiently?

Cheers!

Matt