I am the director of a Graphic design and Marketing company based in central Hertford and we produce these for our clients all the time. I would be more than happy to supply you with a quote for these - especially as I am ex-guide myself! Is it just hoodies that you are looking for or T-shirts as well?
If you can in-mail me and let me know a bit more about the quantities that you require, the colour of the hoodies you would like (we can supply quite a range), whether they need personalisation and the type of design that you would like printed / embroidered on to the Hoodies and I can quote from there.
@Admin, hope this is ok? never sure whether I am allowed to offer to help people or not?