Sorry to hear about the loss, im surprised there werent others due to the tossers coming racing by the pier on boats and jet skis all day roll on the winter. There was even an ignorant bell end in a red boat from blyth with pot ropes about 40yds out literally right round the round end of the pier right up to the post. Absoluely crazy and without a toss for anyone else.
What bait did you have on at the time btw? Been thinking about this, I was on the pier yesterday and have rarely seen so much feed in the water, bait balls everywhere. There were sprats and Sandeel being chased by bigger launce and you could see the odd mackerel breaking the surface amongst them. There was also quite a few codling, dabs and coalies about along with the mackerel. I've never heard of many tope being caught locally but they get them not too far away in yorkshire. it wouldn't surprise me if it were the culprit if not a seal. Either would have your rod away in a flash as they run very fast. A decent cod would give you a decent lunge but it would probably give you time to grab the rod.