Talking of unhooking mats. They are by no means a guarantee of total safety for the fish. Many are a little small and some are a little thin. Even some of the really thick beanie mats are not great for big fish. They compress with the weight of the fish and can go rock hard. They have been responsible for a few smashed tails, not to mention carp being bounced in the air when somebody has knelt on the mat.
Before their introduction caring anglers used to seek out the softest most fish friendly area of the bank side to do their unhooking. This appears to have now gone out of the window. The amount of times I see anglers arrive and just casually throw their mat down without a second thought is amazing. Obviously if you are fishing a fairly new gravel pit it may be Hobson’s choice, but if there are options just give a little thought as to where the best location for un-hooking may be.
Treat your unhooking mat as the last finishing touch to your fish safety considerations not your one and only consideration.