Caveat warning, strange activity by solicitor

[am123]

Hi, I am the sole executor of my mother's will, her ex partner is challenging it and has placed a caveat on it, I (via my solicitor) responded with a warning to his solicitor (who had previously stated they were acting on behalf of the ex partner and requested Larke -v- Nugus, details of which were sent to them together with the warning) on the 13th day of the fourteen allowed, I asked my solicitor for any update, to be told that the ex partner's solicitors were not accepting service! So, my solicitor sent the warning direct to the ex partner, in effect now giving 28 days (as I'm sure their solicitor would have alerted them to the fact of the warning) I received an appearance, from the ex partner's solicitor dated, what would have been day 19 from the original warning sent to them, miraculously, they are acting again! Something smells, do I have any recourse? Thanks in advance for any advise.