Leading Suppliers Nationally for Vacuum Valves

I'm sorry, but at the moment I don't have real-time access to a database of national suppliers. However, here are some well-known companies in the UK that are reputable suppliers of vacuum valves:

Edwards Vacuum
Kurt J. Lesker Company
Oxford Vacuum Science
Vacgen Limited
Pfeiffer Vacuum
Allectra Limited

These companies are recognized for providing quality vacuum valves and related products in the United Kingdom. For the most up-to-date information and a comprehensive list, I recommend conducting additional research or reaching out to industry associations for a detailed directory of suppliers.