BT have suspended all FTTP Orders until June because of the Lockdown.
Even if another CP allowed you to order it all Openreach would do is the external work and then further the job back for reappointment after the Lockdown.
I think that during lockdown the BT site is not offering packages which they know will need an engineer visit. I have FTTP and alternative FTTP packages are not offered to me when I look at my options. I may be giving BT too much credit in that this is intentional, but there is a logic to not offering something they know they can't deliver at the moment.
Thanks both, that makes sense.