icloud not syncing on wifi (but on cellular yes)

I have a problem in that my three Apple devices (MacBook Pro, iPhone 7 and iPad Air 2) cannot sync with iCloud over my WiFi connection, but they all connect to iCloud fine when I go on to a cellular 4G connection.

All three devices are updated with the latest firmware and connected to the same iCloud account, this is confirmed as I can see all the devices that are connected via the iCloud settings.

Problems include not being able to upload/download to iCloud, nor sync photos, notes, files etc, it is pending indefinitely, as soon as I disconnect the WiFi and connect via cellular it works fine.

In general the WiFi connection works well, and I can access the internet and do video calls with no problem. I can also upload files to Dropbox for example with no problem, the issue just seems to be connecting to iCloud over WiFi on all three devices

I haven’t been able to try a different WiFi connection, nor do I have a LAN port on the MBP to test if that resolves.

Please, if anyone can suggest any solutions I would be very grateful :)