Hi,
FTTC. Isnt the plan once 75% in an area take up FTTP then all copper services are withdrawn?
That is something of a misunderstanding. Once Openreach has 75% FTTP coverage in an area then they will not supply new copper services (i.e. ADSL and FTTC) to those who have FTTP coverage. Those without Openreach FTTP coverage in those areas can still order Openreach copper based services (with the exception of PSTN of course as no-one can order that now).
Note that all of this applies to Openreach only. The presence of another fibre provider in an area isn't going to suddenly make Openreach withdraw their copper services - that would be commercial suicide for Openreach.
In the longer term, when Openreach is closing telephone exchanges, the presence of other fibre providers might make a difference to how Openreach handles areas which do not have FTTP or FTTC coverage - if it isn't economical for Openreach to provide FTTC/FTTP in an area but there is another provider who offers it then Openreach might choose to cease service in that area altogether. That issue is at least 6 years into the future though and it might be that Openreach decide that withdrawing from some areas isn't something that they want to do anyway.