Hello

Some of my cells contain, amongst other text, times in brackets in the following format: (tt:tt) eg (23:54).

I'd like to search for these using a formula and so for example use

=SEARCH("(??:??)",A1)

and to trigger conditional formatting

=ISNUMBER(SEARCH("(??:??)",A1))

These all work but of course also detect alphabetic characters like (ab:cd)

I'd like to perform a search that only detects numbers or even better a valid time between the brackets, is this possible please?

Thanks
Robin