£27 seems a lot of money just to play with a hub manager that is severely locked down and very little different from the Hub6. Your money, your choice.
If you only want it to play with the hub manager, don't connect it to line then BT will definitely be unaware you have it.
IIRC from other threads, the OP is, or at least was, running a HH3, so an upgrade probably due! But SH2s seem readily available from Facebook Marketplace for a tenner or less.
Yes, not connected so precisely, my choice.
As already stated, BT knows what router you are running, and quite frankly I'm sure they don't care lol ! If you're happy then so are they...
I think you are missing the point, the OP doesn't want to prejudice being sent a new SH2 when moved to DV.
There is no 'latest' SH2, they are all the same. The firmware is automatically updated online and will always be the latest version.
BT would send a free (loan) one if DV is compulsory.
I suspect a lot of ones that are for sale, have been "stolen" from BT, as they are only loaned, unless they had been purchased retail, or on a very old contract.
Some of the sellers may find that they get a request to return the SH2 or get charged, if they move ISP.