I have contacted customer care as advised and explained what i want to do, the woman spoke with her manager and then transferred me to another team. I explained again what i wanted to do, she spoke with her manager, and they have now made a request to some technical team to see if what i want to do is possible.
My next question, if i cancel line 1, so i keep line 2 with the phone number i require, can i then arrange for an engineer to visit to physically swap the phone line wires round in the box on the side of my house?
I know from a previous engineer visit that this can be done as he accidentally swapped over the phone numbers.
This may be easier to guarantee that i keep the correct phone number
I think everything will now be resolved. I have spoken to someone who has cancelled the line and says the number will be swapped before the line actually goes dead, so should be fine.
In regards to the wiring, an engineer visited when i had a fault on one of the lines and he made an adjustment in the cabinet on the street. When he came back, both lines were working but the phone numbers for each line had been swapped, so it is possible to change the line numbers over in the cabinet in the street. The engineer also told me that there are four wires in the cable, 2 for each phone line, so it would be possible to swap the cables in the brown box on the side of the house to change which physical lines in the house are connected to which of the two lines available.
Hopefully the numbers will be swapped in the next 10 days or so and i have been told to ring back in 14 days if the numbers have not been swapped, before the line is actually disconnected in 30 days from now.
Thanks for expanding, I'm glad to hear that things seem in hand. Please keep us posted here & we'll support you as best we can should things not play out as expected - or let us know if there's anything else we can assist with in the meantime.