Thank you Katie & Emma, your help has been immensely appreciated in sorting this issue out.
Sharing some wisdom to anyone moving out of Virginmedia (in the same area code) to a VM non-cabled street within the same town/area.
a) The safest way to ensure landline continuity is by arranging the landline transfered across to your new provider while living at your old address i.e just before your home move. This way you will make sure you have very minimal interruption of 1 or 2 days of switching sevices after your home move. In my case it was nearly 45 days and my life was hell becuase of my work from home situation with colleagues not able to reach me, and of course Covid did not help either.
b) Landline number porting between Virginmedia and other providers (within same area code) after moving home is still possible, however it is indeed a complicated process, depending on various other parameters.
c) By regulation, Ofcom allows number porting while you are the same address. If you move out and attempt to port, it is not covered by regulation and it is only done as a 'favour' by providers.
d) It is not always possible to do a) for various other reasons. If that happens please make sure your new provider (also called gaining provider) initiates the porting request with correct details. If the porting request(usually an automated process called number import/export) did noto work, then the gaining provider had to acquire the old connection number via "escalation" via Openreach. The escalation email is migration.services.escalations@openreach.co.uk Please note, as a customer, you cannot email Openreach directly, this has to initiated by the gaining provider (i.e your new landline provider)
Hope this helps!