On reflection, and with prompting from the Daily Mail, I realise my criticism was unfounded. Although the headline seemed clumsy, by the time I had looked at it afresh I realised it was grammatically correct.
It read “It’s time for us mums to go on strike.”
If it had read “It is time we mums went on strike” I would have been correct. but the use of the word ‘for’ meant the sentence, without ‘mums’ would read “It’s time for us to go on strike.” which meant they were right. I stirred up a hornets’ nest on Mailonline. Good job I can recognise when I am wrong. I feel a bit of a twit but I don’t think it will stop me. I have given up with ‘different from’ as nobody uses that any more but will take more care in future before I comment on line.