Thanks for your answer JGM. I will pursue your recommended course of action but I have some additional questions regarding how best to terminate future payments and recover money already taken.
For the contracted headline advertising fee of £873.6 (but not including the extra charges revealed in the small print):
1. A deposit of £218.4 was required which I gave the saleman our company credit card which has been subsequently charged.
2. the balance for the 24 month period is due to be paid via direct debit on 6 monthly instalments commencing this month.
Would you advise me to request recovery via my card issuer, and to cancel the direct debit instruction submitted to my bank?
Is there anything else I should do to avoid any claims for future payments built into the small print of the contract such as the agreement automatically renewing, annual extra charges not included in the headline contract amount for "artwork" and proofing, and so on?
Thanks in advance.