Found another caterpillar on the doormat. This time the photo shows it with it's head out. This species will change its appearance to look like a snake when it is threatened, or sees a bird interested. It is really fascinating, however my wife is a bit freaked out by it.
Once I had seen me and i went to move it, it had already started
to look different.
Put this on twitter as was told there is probably a willowherb or fuchsia nearby and they are looking for somewhere to pupate. Those two now in my back garden. Apparently though there could be as many as 50 in one batch!