It sounds as though although ‘new build’ , your property is also an ‘in fill’ , in that it’s been built in a vacant plot ( or a site were an existing property was demolished and ‘new’ buildings erected ),so although ‘new build’ , the usual ‘new build’ policy of Openreach doesn’t really apply, the main factor on what speed broadband service you would likely get is what is available to the adjacent more established property’s.
If you enter your nearest established property’s details into the wholesale checker , that should give a reasonable indication of what you are likely to get, if the area is served by telegraph poles then service should be straight forward , if the other property’s are served by underground ducts, then what the builder/developers has done may determine how quickly ( or slowly) service is available, as if it’s underground and the builder hasn’t provided duct to the curtilage then a delay is inevitable.
10Mb is a speed that could be delivered by exchange based ADSL2 or ‘fibre’ FTTC if the distance to the cab was relatively long....although the fibre to the premises network is getting larger all the time , it’s still likely that it’s not going to be available to you or your more established neighbours , checking what the neighbours can get will show if FTTP is available, but if 10Mb is the ADSL speed for your general area, and the representative didn’t want to ‘offer’ more than that in case it were the best on offer, perhaps better speed may be available from FTTC.
Posting a near neighbours results from the wholesale checker ( one that is served from the pole nearest to you that will also serve you ) that will show what you will likely get once your address is able to order service.
https://www.dslchecker.bt.com/
