Having recently won a Listener prize, I am rather chastened to be struggling with this one!
Nevertheless. for those who do not fully understand the algebra of surds (the roots of numbers that are not themselves perfect powers), the key equation is this (using Rt as the Square Root sign, & ^2 for squared):
(b + c x Rt66)(e + f x Rt66) = (b x e) + (((b x f ) + (c x e)) x Rt66) + ((c x f) x (Rt66)^2)
= (b x e) + (66 x c x f) + blah
(b x e) + (66 x c x f) = G -> crucial to the solve!!
blah = h x Rt66, and is irrelevant.
Hope this helps someone; in the meantime I am sure that I have nailed A, O , S & U to being consecutive larger numbers, but can't quite work out which is which...