Hi. I’ve just chosen you as my new provider but I’ve not had any details on wether you inform my old provider or not? Is this something I will have to or do you do this for me?

Doing your own research is the way to go, rather than waiting for replies on a forum.

See: https://help.bulb.co.uk/hc/en-us/articles/360016445831-What-happens-when-I-switch-to-Bulb-