So it seems the expansion since the announcement last May amounts to another 5 sites; Carmarthen, Harrogate, Newport, Romford and Sidcup.
Harrogate and Romford were already open in May last year, so opened up after the fact, but the others are newly opened sites.
The Tesla website is currently showing superchargers open to non-Tesla as separate markers so I thought it would be useful to grab a screenshot to track the opening up of the network in the UK (I don't always see an option to filter on Non-Tesla SuCs):
(The orange circles highlight the changes since the original 15 opened on 18th May 2022, which are shown in a similar screenshot
here).
I checked at the start of January at which point the original 15 sites plus Newport were open to non-Tesla cars. So to build on
@Sean. 's post I think the timeline so far is:
18-May-22 (15 total): Aberystwyth, Adderstone, Aviemore, Banbury, Birmingham - St Andrews, Cardiff, Dundee, Flint Mountain, Folkestone - France Bound Only, Grays, London - Uxbridge, Manchester - Trafford Centre, Thetford, Trumpington, Wokingham
09-Dec-22 Newport (available to non-Tesla as soon as it opened)
??-Feb-23 (3 total, all legacy sites): Harrogate, London - Romford, London - Sidcup
21-Feb-23 Carmarthen (available to non-Tesla as soon as it opened)
I'm not sure exactly when Harrogate, Romford and Sidcup were opened up to non-Teslas but it was some time between early January and the end of February.