I get double the speeds showing on the availability checker. I currently get around 8-10 mbps with adsl 2+. So i imagine i'll get around 5-7 on fibre but won't hold my breath as i know the drop off after 2 and bit km is pretty steep with vdsl.
I'm currently around 3.2km from the exchange and 2.9km from the cab. That's by road which i think the line follows.
I honestly just want to try fibre and see how the line handles it at my current distance but current prices for fibre (38mbps) and cancellation charges are stopping me. That's why i'm hoping for a cheaper upto 18mbps option.
Thanks for the warning though. Much appreciated!