Ask the gas company if any works are curently been carried out to you're area gas main. If not then ask a local "Gas Safe Registered engineer" to pressure test for you at the meter and you're appliances. Likewise as my fellow ABer gucciman has expressed one is curious as to how you seem to think you have a supply problem ??? More likley to be an internal problem, undersizing of pipework or incorrect commissioning of appliances i would suspect !!!
If your flame rapidly fluctuates from large to small it is more likely to be a problem with the governor than the actual supply. The old ones with built in filter were prone to this.
They belong to National Grid or your shipper, who will replace a faulty one at their cost.