Broadband Installation at a new address (but wanting to take landline number from previous address)

[DeadPixel]

Folks,

Following on from an earlier post, I thought it might be quicker to get an answer from the experts here than phoning.

The background to this is as follows:

• I'm not currently a NOW Broadband customer
• At my current/permanent address I have a BT Landline and a no-frills non-fibre ADSL2 service from another provider.
• Due to unplanned construction work at my current address, I have had to move to temporary accommodation - and may be there for anywhere between 6-12 months (could be even longer, who knows!) - eventually returning back to my original/permanent address.
• I am considering taking NOW Broadband's Super Fibre phone & broadband package at my temporary accommodation (ceasing the BT Landline + ADSL2 service at my current address). Assuming everything goes smoothly, I may then consider keeping the NOW Broadband service beyond the original 12 months contract (and may also [hopefully] have moved back to my original premises in the meantime)
• The temporary accommodation already appears to have a BT Openreach 5C master socket - although the existing line will likely need to be re-activated by NOW.
• The location of the temporary accommodation is within the same exchange area as my permanent address and so it should be possible to keep our existing landline number (BT have confirmed this for us) - in fact, it is essential that we keep this existing landline number since we've had it for close to 40 years and it would be a real pain to have to notify everyone of a new number - not just close relatives, but various services, businesses, banks, medical agencies etc - it should be easy enough to remember the big hitters, but we'd inevitably end up forgetting someone/thing in the process. I appreciate that in some large population areas or cities with good 4G/5G mobile signals that many people are forgoing landlines and opting to only have mobile phones instead - however, we live in a pretty rural location and whilst we do have mobile signal, its not reliable and landlines are still seen as a pretty essential utility - even now - every bit as important as broadband.
• In the interim period, whilst I try to sort all this out, we're just getting by on our mobile phones for calls and basic data needs (using our phones as personal hotspots)
• I've read some horror stories in various places regarding number porting issues and NOW Broadband sometimes having issues porting in numbers from another provider and when it goes wrong it does seem that there is very little recourse unless you really really REALLY persist in getting it sorted out - not sure if that is still a big issue today.
• As part of my investigations, I've been speaking both to BT and the company which currently provides my ADSL2 broadband to get an idea of what is involved in moving my existing phone + broadband services wholly either to BT, or to my current broadband provider, e.g. costs, timeframes etc
• Because we want provision a phone + broadband service at a new address and take our existing landline number with us, the suggestion was to initially sign up for the combined phone + broadband service at our current address and then request a house move to our new/temporary accommodation - as opposed to just signing up for a new account at our new/temporary accommodation and ceasing service at the previous address and taking the existing number with us.

With all that in mind, I have a couple of thoughts/questions:

1. If I did decide to sign up with NOW Broadband, is that the approach I should take, i.e. get it provisioned at my current premises first (ceasing the existing BT landline + ADSL2 service) - allowing NOW to port in the existing landline number from BT and THEN request a house move to our temporary accommodation. Whilst that might work, it seems a longwinded way to do it - rather than just getting the service provided at the temporary accommodation right away...?
2. Is the approach of getting NOW Broadband provisioned at my current address first, before requesting a house move to the temporary address the 'safe' way to do things in terms of porting in the existing landline number - or could we still experience potential issues with the moving the landline number to the temporary accommodation - even if the original port into NOW was successful and the new address is still within the same exchange area?
3. Are there any additional costs I should be thinking about if I decided to get the service provisioned at my current address before almost immediately moving it to my temporary address versus just getting the service provisioned directly at my temporary address right from the start and ceasing the services at my current address - maybe the new provider (NOW) can't cease services for a different address to that which the new service is being provisioned?

Apologies for the longwinded post, but hopefully you get the gist of where I'm am with this. Feel free to ask for additional info if you need it. Much appreciated.