I am having Talk Talk come and fit a Line from them as Taking phone service from them and having a new line put in by them and wanted to know is it them who fit them or do they get someone from BT to fit them as ive never seen a Talk Talk van around before.

If Talk Talk now offer line connections, they will, like all* the other 'line providers' now in the market, have to employ Openreach to undertake the work. Only Openreach (a BT company) are allowed to undertake work on the PSTN.

* The only exception is Virgin Media who have their own engineers for their cable network.

I would avoid "Talk Talk". Their lines get crackles on them. I know from experience.

They have some dodgy routing of calls, can be very poor quality, often dreadful to mobiles.