Would be interesting to see what happens if 4x 1gbps connections are requested. The entire PON only has 2.4gbps...
SIN 506 explains that Openreach only commit to 110 down on the 1000/115 product. Interestingly, they also commit to 110 down on the 160/30 option. In practical terms they have been so conservative with the CIRs on GEA FTTP that I'd doubt they'll ever be a problem.
You'd have to order and saturate 23 services at 160/30 or higher for Openreach to be in trouble - and all the ONTs (between 6 and 23 depending if 4 ports are available) would have to be connected to the same PON. 23 services at ~£25 per month is over £550 per month at which point customers would just have ordered a 1G leased line.
You could do it with 8 services at 1000/220, but comparing Openreach prices for just the tails:
1000/220: £1009.68 rental p.a. plus £500 install
8x 1000/220: £8077.44 p.a. plus £4k install
These services would come with a committed total download rate of 2640Mbit, and 1760Mbit up.
EAD 10000 £4980 p.a. plus £5441 install
... and this is 10000 committed up and down, all day and all night.