It is probably a combination of things. People aren't spending as much on non-essentials, and also auctions don't seem to be as popular as they used to be. Unless it is a very desirable item, lots of auction items seem to go round & round unsold, or often only get the opening bid. Perhaps switching to 'buy it now' for some items might help? 

Also, it looks like you are using Simple Delivery, and if so, I'm not sure why your postage price is set at £4.06? I tried a 'sell similar' listing for one of your items, and I was getting £3.38 for an up to 2kg parcel. My postage setting are for Royal Mail only - maybe you have different couriers enabled?