This is a cassette mix found by Andrew Curley in a delve through his tape cupboard. Unfortunately the first part of the mix is corrupted with silence, so this rip begins from about 30 minutes in and all of side 2.
The full mix is interspersed with samples from Night Moves (The Professional Approach To Disco Dance Instruction) [K-Tel, 1979].
First 15 minutes contained amongst others Hacienda - Diskoking (Ian O'Brien Remix).
No idea whether the rest of the Toolbox Trilogy exists anywhere, one can hope it appears someday