Thankyou. I was thinking of Wellington Court, round the corner in the part of Glenbuck Road nearer the station. Saxon Close is on the site of the old British Road Services depot (latterly Roadline, and then briefly used as a warehouse before it burnt down in about 1982). Comparison of the old maps
here and
here suggests that most of that site was never actually part of the goods yard, but it's not surprising that at least part of it was railway property.
I had a quick look at the documents online (thankyou
@Highview for the link), and went to the consultation today. (You go in through the old ticket hall, but most of the exhibition is in the space behind which was presumably the office behind the ticket windows). The staff appeared to have at least some knowledge of the area. They said that surveys last year had indicated a maximum car park occupancy of 297 (so if anyone has evidence that that's wrong or out of date, you'd better tell them), that the council were quite keen on having a smaller car park (presumably because it would mean fewer people driving into Surbiton, I'd guess), and that SWR were keen on maintaining car park spaces (although it seem to me that they could benefit to some extent, if people driving in from further out were to use their local stations instead). I think it was envisaged that residents' parking schemes would prevent rail users from parking in the nearby streets, but that's presumably a matter for the council rather than Solum directly.
I'm not convinced by the idea of a 17-storey tower, which is about twice as high as any other flats in Surbiton. They said they'd looked carefully at townscape, sight lines, etc. and thought it wouldn't be very obtrusive; maybe they're right, but I hope it wouldn't set a precedent. It wouldn't surprise me if they're asking for 17 in the expectation of getting permission for some smaller but still large number.
In principle I think high density development near stations is probably a good way of providing necessary new dwellings without building on green spaces or increasing car dependency, and fewer people driving into Surbiton probably is a good thing in many ways (depending on what they do instead), but there might be problems with this scheme in its current form.