DB6
PPL (no IR) CANNOT go through Class E at night. Nor can he climb above 6000 in the Scottish TMA Class D because it isn't a Control Zone (CTR) but Class D TMA.
South of the border, TMA tends to be Class A therefore, no IR, no entry.
The Glasgow and Edinburgh CTRs are Class D and extend from the surface to 6000. The Scottish TMA is Class D and extends from 6000 to FL245 (if I remember correctly - no map in front of me!). Since the TMA is not notified as a CTR, no SVFR is allowed.
If your PPL wanted to go from Dundee to say Carlisle at night he could either:
a) request to transit either the Edinburgh or Glasgow CTR SVFR, then stay below the Class E once through;
b) go between the two via Cumbernauld but stay below the Class E (ie below 2500); or
c) go east of Edinburgh via North Berwick and stay outwith the lateral limits of controlled airspace of any class up to FL245.
I hope thats clear.
Class E airspace really is a waste of time - no requirement for VFR by day to contact ATC and therefore it isn't a known traffic environment and so there's less protection for IFR flight in this airspace, especially with all the military activity in that part of the world. When I was at EDI we tried for years to upgrade the Class E to D and raise the base but nothing ever happened.