Hi - as a complete 'Wealdstone' ignoramus, I'd say definitely nothing to do with W.10. W.10 does have a similarity with your bowl, insofar as they are both 'footed' and have everted rims, but there the similarity ends - as you say, W.10 is a vertically ribbed pattern, no swags in sight plus W.10 is a bucket shaped piece.
Wealdstone pattern Nos. for 1931 - 34, in the Wuidart catalogue, seem not to follow a design format that shows a logical sequence such that we might say, for example, W.1 through to W.25, are all swag moulded, and all W Nos. after that are rib moulded etc.
In fact, W.1, W.3 and W. 10 are all rib moulded - and W.9, W.8 and W.18 are all horizontal swags - so Nos. seem to be random as to moulding and would be unreliable for making a safe deduction as to whether a piece was swagged or ribbed.
The pattern Nos. run to quite high digits in the 'big book', so presumably there were a lot more shapes/patterns made than are shown, and unless we can see the entire range then we may never know. Shapes in the swag moulded design were certainly made with a foot, so in view of the quantity of other patterns/shapes that we can't see, then we can't say with certainly that yours couldn't be one of the shapes not shown - it may well be.
There is a Pattern W.5/W, which shows a horizontally swagged bowl which appears identical to the one here (in terms of appearance of the bowl part) but it lacks the foot that this one has - unfortunately, the original catalogue omits any reference to sizes - you might ask your acquaintance for their opinion on that suggestion. Many glass houses offered similar shapes/patterns for a given bowl for example, and it would be offered with and without a foot.
Generally, the differentiating feature, when compared to Webb, is that the latter moulding is waved rather than swagged as with the W/Fs. pieces, but the trouble is that other companies may have copied or had their own take on these designs. Is it possible the one here is a Scandi piece do you think?
Looking at the first Wuidart catalogue page in 'the big book', for Wealdstone' pieces, the colours available for Wealdstone were ........... gold/green/violet/lido blue/royal blue/peacock blue/silver grey and helion .......... no mention of clear?? The water in a lido always seemed cold, when I went swimming - a few years back.
As far as I know, and supported by the Jackson book which accompanied the W/Fs exhibition at the Museum of London a few years back, this museum may possibly possess more information on shapes and patterns of Wuidart material, so contacting them might help.