Why not go directly to Plusnet?
Because JL unlimited is £ 5 per month cheaper than Extra (market 1 area as i am) as you would need to buy the pro add on at £5 per month to enable extra to have full line speed like the Unlimited package has.
Also as you have said extra has a only 60gb limit which is not enough
This is what the JL sites say about its unlimited bb
JL website says they charge the same price regardless of where you live.
Unlimited usage
Simply put, there are no restrictions on how much you can download, allowing you to enjoy all the internet has to offer. Download as much or as little as you like, whenever you like.
Can a PN rep kindly answer my query in my first post. thank you