Assuming the same number of hours for each what’s the difference in price for training.
Not sure on the difference in price but finding someone might be difficult. Since the age dropped to 18 for hgv, there is little call for just 7.5 ton training as you might as well go for class 2. I looked into it and none of the companys near me had a 7.5 t vehicle to train in, so I put my employee through the class 2.
LASHHGV:
Assuming the same number of hours for each what’s the difference in price for training.
from what I know there isn’t much difference you would be better off just doing your cat C then you automatically get your 7.5t on your licence
Ta for that the info was actually for my wife 
She’s looking to start training I already told her to go straight to class 2.
A company near us trains 7.5t in a large van.
LASHHGV:
Ta for that the info was actually for my wife
She’s looking to start training I already told her to go straight to class 2.
A company near us trains 7.5t in a large van.
Wasted money and time going for 7.5. Start Class2 instead.
There is not usually a big price difference in the two but it can be easier for many who just want C1 to do it in something like a 5 tonne van which is virtually the same size as something like a 3.5 transit van
The downside is that passing in a van is a lot different to driving a 7.5 tonne lorry with air brakes etc
Does your wife want this for private driving like a personal horsebox?
As LashHGV says above, C1 is often done in a 4t Sprinter just to save fuel and improve chances of a first time pass.
If you are only ever likely to drive a 7t horse box for instance, then C1 is all you need and can save you a bit.
If you are using it as a stepping stone towards higher categories, don’t bother with C1 but start at Cat C
Go straight for the class 2. you then get both!