Fibre questions..

[#1]

Hi everyone,
I recently ordered Plusnet Unlimted Fibre but after doing some digging around I have a few questions:
1) Why does Plusnet offer me fibre but I cannot get BT infinity? I thought they were both owned by the same people?
2) I have been quoted 42mbp/s download - does anyone know a estimate of how far I am from my cabinet? Apparently I am on Cabinet 9 on Thamesmead Exchange
3) I currently get around 9ms ping from BE - will this ping improve/get worse? What could I expect for latency?
That's all for now I think.
Thank you.

[#2]

1. Unknown - maybe the records are wrong (either at PN or BT) - just keep your fingers crossed.
2. My next door neighbour gets around 30mb download on her FTTC (TalkTalk) while I get up to 74Mb connection (usually around 65-70Mb). I had an estimated connection speed of 50Mb. I think they may base the estimates on the speed other FTTC users get in your general area.
3. My speedtest pings are around 5-8ms. The ones I used to get from BE were 25ms-40ms for the same tests.