Activate Acrobat 8 - LOCKED, dead product

I’m in the UK and am trying to activate a previously-unused copy of Acrobat 8 Pro which was still in its shrink-wrap.

The Activate option under Help was disabled, so after a bit of googling around I downloaded and installed the Licensing Repair Tool from www.adobe.com/support/contact/licensing.html.

This enabled the Help|Activate button but when I click it a pop-up headed “Internet Connection Not Detected” appears and offers 3 options:

1 - Retry activating
2 - Adjust your Internet connection ... if you use a proxy
3 - Activate over the telephone

1 never succeeds. 2 is pointless because I don’t use a proxy - I have a bog-standard Win10 (Home, 64-bit) laptop connected to the internet through a standard broadband connection which is working fine for everything else. For 3 I tried the 2 UK numbers but they are disconnected, so I phoned the US one which announced that Adobe not longer supports telephone activation and pointed me to www.adobe.com/go/activation but that contains, afaics, no information whatever about activating Acrobat8.

I have checked that my computer’s time and date are correct.

So my question is, how **do** I activate this never-previously-used copy of Acrobat8. Btw, the fact that I’m trying to do this on Win10 is irrelevant (though google finds plenty of Q&As saying there may be problems with Acrobat8 on Win10), because I don’t believe the dead-ends I’ve run into are anything to do with Win10 and I have had Acrobat 8 (with different serial number) running faultlessly on an identical Win10 laptop since Win10 came out.

Thanks, Martyn