Beemans are ok if you sort out the common fault - a burr on the inlet hole which wears the piston o-ring. 2 seconds with a bit of wet'n'dry will sort it.
Not particularly compact, but light enough. Rather loud though, and quite real-steel looking to the uninitiated. You could maybe pick up a 2nd hand one for £40 or less?

One of the old Webleys - Junior, Premier, Senior, and as you said, the Tempest fit the bill for pocket sized. Record Jumbo too, if you can get hold of one.

The new Umarex buckmark, whilst 12" long, is otherwise compact, light, fairly quiet and pretty accurate. If you order one from Fritz like I did you can get it for £40 new.