Next best for this boxset seems to be £26.69 at BlahDVD/101CD. Must be an old or deleted release as no other retailers seem to have it.
Cheapest individually is as follows:
The Ipcress File (£7.39)
Educating Rita (£4.99)
The Fourth Protocol (£3.99)
TOTAL = £22.76
A special edition four-disc set containing four of Michael Caine's many memorable feature films. From his classic first outing as London spy Harry Palmer in THE IPCRESS FILE (1965); to the period battle drama of Robert Louis Stevenson's KIDNAPPED (1971); and the loveable drunken tutor in EDUCATING RITA (1983) and full circle to play a spy-catcher in tense thriller THE FOURTH PROTOCOL (1987). This is classic Caine.
Don't forget El Quidco.