BT; I think Plusnet; vivaciti. Obviously others, but that's three. The first two you may need to educate the people you speak to .

Technically you shouldn't need to take broadband from the new line rental people. You just need a "LORN", (Linked order number) that you then give to your chosen ISP, but that means possibly educating both companies and it going wrong anyway. Apparently it does even with just the one. You can't order PN phone without broadband either.

PlusNet sales are quite versed with the procedure

Zen will do simultaneous provides as well