Sure does. Judging by the close proximity of the roof gutter drain pipe, the area has enough moisture to make an earwig family quite happy.

It's a very dry area Loosestrife as the drainpipe feeds my water butt which has been empty for ages as we haven't had any rain to speak of for 3 weeks so the only water comes from me watering the planter. Would that be the reason for them being there?

Yes. If you can try going out at night with a flashlight and move the planter to get a positive ID. They can make a mess of the flowers can't they. On the positive side they do kill and eat slugs and aphids. If you consider them to be causing you a major problem you may try a non poisonous control such as a sprinkle of diatomaceous earth to limit or solve the problem.

OK thanks for your help, I didn't realise they killed slugs - good on them ! :-)

Earwigs have a bad reputation but they do walk a fine line between being considered a beneficial insect and a horticultural pest. My flowers no, but they can hang around my hosta all they want. The little holes they make is nothing compared to what slugs can do during the night.