Thats me all moved across to
https://www.webhosting.uk.com/ My domain still goes to the old hosts, but that may just need a bit longer to update. My domain is with 1&1/Ionos, and all I had to do there was update the name servers (after setting up email accounts/forwarders), everything else domain related is pre configured at WebHosting UK.
You do need to set up the email accounts up first, then the forwarders if you have any, as it won't let you configure a forward that uses one of those email accounts until its setup.
Another catch is when setting up the email accounts, you can send a welcome email, but that ended up in the new account, and I'm sure I hadn't updated the nameservers at that point - but you can easily lookup these details, or open the new account in webmail.
Once I changed the name servers, email was instantly going to the new accounts.
This mornings job was to migrate the email using
https://imapsync.lamiral.info/X/ which worked perfectly on three accounts, the fourth account kept failing authentication with the old host. No idea why, but I re-entered the same password at the old host, and then it worked, Outlook had no issue accessing the account, so the password was correct - weird!
Then all that remained was to update the clients, and job done, so long as I haven't forgotten something.
I'll give it a week, and then delete everything at hi2