First of all, congratulations on finding such a lovely set! I rarely get excited about trinket sets, but yours is a fantastic design and looks to be very good quality. I have seen the tray before, but never a complete set. I'm sure Pamela used to have an example of this tray on her site listed as unidentified, but I can't seem to find it now...
Regarding maker, I would think it's probably not by Jobling. It's not shown in the Jobling catalogues, nor in any of the Jobling adverts I've seen to date. That in itself isn't entirely conclusive though as there are several designs which are now known to be Jobling which weren't feature in their trade catalogues.
Like Anne, I thought Reich was a strong possibility when I saw this set. The colour, finishing and general look of quality is consistent with their better pressed items. I don't any complete Reich catalogues to compare with though, however, I believe the 1936 Reich catalogue is available from Siegmar Geiselberger at www.pressglas-korrespondenz.de
He has always been very helpful when I've made enquiries in the past.
Another possibility could be Schweig Müller. I'm not really familiar with their output, and don't have any catalogues, but it might be worth seeing what you can find. I think it's likely your set is continental rather than British.