Hi Danny,
I'm looking into it now.
(£18.25 is the price for an Under 16 Off Peak return (Valid at any time) if anyone is wondering...!)
Harrogate-Manchester Stns £9.10
Manchester Stns - Acton Bridge £5.50
Total = £14.60
Not much of a saving but it may be possible to do better than that....
Edit:
If you get TPE trains that call at Stalybridge you can save a little more:
Harrogate-Stalybridge £7.65
Stalybridge-Acton Bridge £6.20
Total = £13.85
I can't find a cheaper combination than that, but maybe someone else can.