I would suggest a folding grapnel anchore like the ones listed here
It folds away with no nasty pointy bits to damage your boat! Add a couple of metres of chain to it and about 30 metres of rope. Alternatively don't attach the rope permanently, but carry it aboard for general use as a long mooring line, tow rope, clothes line whatever -- but make sure you can attach it easily when necessary!
It will be useful any time you have engine trouble and are being taken the wrong way by the wind and tide. In a wrost case it will stop you being blown onto a rocky lee shore. You wil rpobably find that where you go boating in Scotland it's not possible to anchor far from the shore due to the depth of the water, but in an emergency just let out the full length so it hangs below the boat, and with a bit of luck it will make itself fast before you reach the shore!