I don't think that 25p/text is at all reasonable
This no way relates to the (network) cost of sending the text, it may include some recoup of the system development costs. The rest is profit.
So - BA are profiting by charging us to know about their delays.
If this was a genuine customer service move, it would be free or at a nominal (5p ?) charge per message - maybe in free for elites.
I'll be keeping my 25p.