This has been posted on worldofspectrum.org - a listing of all the ZX81 software titles released by New Generation Software (including 3D Monster Maze).
It is all in aid of Cancer Research UK and has been listed by the daughter of Malcolm Evans (who set up New Generation Software and wrote the software)
http://cgi.ebay.co.uk/260781391438
ZX81 Charity Auction
ZX81 Charity Auction
Rich Mellor
RWAP Software
RWAP Adventures
SellMyRetro
Retro-Printer Module
Also Involved in:
Icephorm
RWAP Software
RWAP Adventures
SellMyRetro
Retro-Printer Module
Also Involved in:
Icephorm