How to sue a Scottish company?

To put is simply, what is the best course of action if an English company needs to sue a Scottish company for none payment of trading debts. 

The transactions was carried out under the English company's trading terms but unfortunately these do not include anywhere which laws would apply in the case of a dispute.

The amount involved is not a lot (under £1000) but it would be a good bit of PR to be able to get it.