For Stu LGS and anyone else needing a helping hand…
Factorise each number ‘block’ in the cyphertext into a product of its prime factors. Then convert each prime back to a letter of the alphabet. (The code uses the first 26 prime numbers).
Tom M(I)1EYP
In reply to M1EYP:
Can we have that in English, please, Tom? 
HC
Brian G8ADD
In reply to G8ADD:
Oh heck; another product of a disfunctional education. It just shows how much standards have improved since the 50s/60s. Interestingly I note that this very code appears in a book “suitable for age 10+”.
73
Richard
G3CWI
(cooking Christmas lunch)
PS the code is fully revealed in my post: Post by G3CWI on 20th December 2011 at 08:39
Well I’ve now done all but one and I cannot find anything in the summit list that matches that one (unless Excel is failing me).
Stewart G0LGS
In reply to G0LGS:
Which one is a problem?
73
Richard
G3CWI
In reply to G3CWI:
Sorted !
I did something silly !
Stewart G0LGS
In reply to G3CWI:
Possibly, Richard! My lot were absolutely **** hot on trigonometry, vectors, stats and calculus but ignored other areas so Tom’s terminology is double dutch to me - though I vaguely remember seeing “factorial” on my first scientific calculator!
Just for reference, I went to a Technical School and left at fifteen as nearly all did then, we had three periods a week each of physics and chemistry, a half day each of metalwork, carpentry and engineering drawing, and I remember a glorious workshop with working examples of every type of engine one might expect to meet with from a beam engine to a small jet! A different world…
HC
Brian G8ADD
In reply to G8ADD:
Brian
This may help:
http://www.mathplayground.com/howto_primenumbers.html
73
Richard
G3CWI