[qwerty123]

That won't happen because a) Today at Wimbledon won't get onto iPlayer and b) they have already committed on air to showing the tennis on BBC Two through the evening to its conclusion.
I think it's likely BBC Wales will get a bespoke bulletin at 23:00 on BBC Two and then they'll show Today at Wimbledon at 23:30. They'll have to find another slot for Countryfile in Wales.

History would suggest it to be unlikely that Wales will get a bespoke bulletin. In the past when Wales has broadcast the news at a different time to England they have simply simulcast the opening 15 minutes of a news channel bulletin which in this case would be from Singapore and surely completely inappropriate.