I did think about switching to Soho::1, but then I found out that the download allowances are per line, so having three lines I'd have to pay triple the advertised rates. So I'm going to leave it for now, but I may change my mind later.
The website is very confusing, as it didn't make this point clear to me, indeed it seemed unclear to staff as one email I got giving me a quote didn't have "times 3" done _correctly_ for my three lines. The website is also confusing in that it doesn't explain that the SoHo downloads of 150-350 GB per line per month are available to BTW and TTB line users but the 2 TB download deal is TTB lines only. It was just assumed by whoever wrote the webpage that the user had read up on Home::1 and would just make the same assumptions.
There were various 404s and new and old versions of pages lying around, as they are now it seems trying to hide away the traditional “units-based” tariff which I am on.
I'm also unclear whether or not the overnight special 02:00-06:00 1 TB-per-unit download rate deal for units tariff users is still in operation. So units tariff users just watch out.