Some similarities to you.I was all set to move to Vodafone ,from BT,for my broadband and considering dumping my landline and use my all calls included mobile contract.
Spoke a few times to BT and ended up getting a noticeable discount off my broadband and retaining my long standing land line number (Only now for a few incoming calls.).£2.00 month. Win win on broadband and landline.It pays to haggle...
Now,let battle commence on car insurance....£200 up to,£600.…I don't think so.