I am moving away from Plusnet so when I move landline to A&A I want to be sure everything phone/broadband/etc at Plusnet will be cancelled? I shouldn't need to phone Plusnet it should be automatic and an easy way to cancel?
Yes, that is what will happen. I had exactly the same situation: I migrated my Plusnet phone number to Sipgate, and that ceased the phone line and broadband from Plusnet. (I had FTTP running alongside it from a different provider).
Does anyone remember Plusnet sending an email when they receive a request to move the landline confirming everything?
Yes. I sent my porting request to Sipgate on 24/7/22.
On 28/7/22 I received an E-mail from Plusnet:
"Leaving Plusnet - what you need to know
...
We're sorry to hear you're leaving us.
Another service provider has told us that you want to move your broadband and phone away from Plusnet.
Your broadband and phone service is scheduled to transfer automatically on 2nd August 2022 and will result in the cancellation of your Plusnet account. This means that on this date, your services will be taken over by your new provider and you won't need to contact us to cancel your service with us.
If something isn't right and you would like to speak to someone about your account, please call us for free on 0800 073 3057 from a landline or mobile."
It carried on to give details of the remaining charge I had to pay (which was £5.15)
On 2/8/22 I received confirmation from Sipgate that the port was complete.