Hi Chris,
Contrary to what BT would say (never believe anything they say....) I would be surprised if you could get fibre into your business as quickly as from the 17th of April to the 3rd of May. We had it installed about 6 months ago, and it took quite a few months from start to finish. First they have to survey, then someone has to pull in the fibre tubes, then someone else blows in the fibre, and finally someone comes to fit the Cisco router and commission it. Even the survey stage to weeks and weeks to happen.
Ours was 100% installed through existing ducts. If there are new works to do to cross a field, I guess that will take even longer. 
Despite all of this, it still hasn't worked at the contracted speeds since installation, and BT will not do anything about it. When set at 100 Mbps, we got between about 60 and 90. So we lowered it to 20 with a plan to see how high it would go before it started to diverge from the paid for speeds. Alas, at 20 mbp, it doesnt even make that either. BT seem unable or unwilling to sort it. And to boot, its had more downtime than the copper backup lines we have with another provider. This despite BT's claims of a target 100% uptime for their business fibre product, BT Net.
How are you for 4G or even 3G down there?
Cheers
Windy