Whilst I was replacing my out of date (when did you last check yours?) standard flares (a red pinpoint and orange smoke), I came across the PainsWessex Compact Distress Signals Miniflare Mk8. The lightweight, Pains Wessex Compact Distress Signal pack contains 3 red aerial flare cartridges and a penjector firing mechanism, all enclosed in a tough, water-resistant case. The penjector is fitted with a stainless-steel spring and striker pin. It features a slot for easy loading and unloading of the flare cartridges. These are stored inside the casing on an elastic lanyard to avoid them being lost when the base cap is unscrewed. Each cartridge projects its payload to a height of over 45 metres, burns for up to 5 seconds at a minimum of 10,000 candela and is visible for at least 5 miles in daylight increasing to 10 miles at night, depending on weather conditions. Operating instructions are on the case.
Pains Wessex Compact Distress Signal are designed primarily for use on yachts, dinghies, Personal Water Craft, canoes, kayaks and sailboards, but have many applications as a general-purpose distress signal for aviation, hill-walking, climbing, skiing and other outdoor pursuits.
Please take a look at the PainsWessex website for more information.
I rather think this piece of kit is well worth buying and carrying with you when out at sea kayaking.
As to where to buy flares without extortionate P&P, especially if you are based inland in the Midlands like I am, I can recommend Norwest Marine who were extremely helpful. Unlike other chandlers, their shipping was very reasonable too. For two flares (Pains Wessex Red pinpoint and Orange smoke) and the Compact Distress Signal miniflare MK they charged me £12.00. Other chandlers had quoted me in excess of £45.00 for delivery!