Roadside Bookseller: Impulse Purchases for Auction

Returning home from the paper shop I came across a roadside book seller with lots of titles for 50p. Decided to buy four - not quite at random, I can sniff a bargain book wise - and try to turn £2 (or £2.10 as the mendicant scoundrel affected to have no change) into, who knows? £10, £20, even £50 with some proficient eBaying.

Have I bought useful titles in this regard?

- Dennis Wheatley Traitors' Gate a new Gregory Sallust story
First Edition 1958 Book Club Edition i.e. pocket format and smaller print.
Good to fine, no pen marks or clipping except neat owners name on DJ which is also good to fine, intact with a few small tears. Street maps of Budapest inside F and B with Plan of Tower of London facing.

- Enid Blyton The Rockingdown Mystery Line drawings by Gilbert Dunlop
First/Third 1950, Collins
Fine + boards and pages, but no DJ except scrap as bookmark

- Capt WE Johns Another Job For Biggles Illustrated inc some pen and wash by Stead.
First edition 1951 and print. Hodder and Stoughton
12th of series. Fair. No DJ. Scouse, untidy scribble of owner. Tape marks.

And finally
- Enid Blyton Naughty Amelia Jane! Illustrated by Sylvia I Venus.
Seventh edition or printing 1947, George Newnes
Tight pages, spine faded, some splash on front cover
Big print for younger children and BNP members

I know, I know, a bag of nails. But I can see a major multiplier on my investment in stock and will spend no more than 30 minutes or so of hobby time listing on eBay ... The Wheatley may do the job on its own. One in a shop for £14.99 though there is a bit of a glut of copies.