Yes, that is a genuine Kintyre Octopus, and the first Scottish Octopus I have met. Safe to say, it was found washed-up on the sand at sunset, where it was subsequently photographed, and then, with help from my significant other was safely deposited in a rockpool to await the oncoming tide.
Perhaps it is needless to say, that Kintyre is a very special place for me, and my nearest and dearest, and this is not in the least because for me to drive there from my home it's a good 7 hour haul! It must be said though, that the majority of that drive is a pleasure.
As was noted in Peter R. Rodger's "Agate Collecting in Britain" agates here are highly waterwashed, having weathered the erosive process twice, presumably firstly being eroded from the Old Red Sandstone, and then being somehow swept-up into the formation of the conglomerate which they are now still in the process of being eroded from. It takes a fair amount of patience, imagination and perseverance to discover how these agates appear in their natural surroundings. Especially since the inner markings of many Kintyre agates tend towards the abstract and unusual, while still including very fine examples of fortification pieces on occasion, which are probably easier to spot, owing simply to familiarity.
Most agates here tend to be between 2 and 4 centimetres, however, I feel I may have yet to see the upper range of sizes here, which certainly reach 8 cm, and perhaps larger stones exist.