I too saw this shard about an hour after Bram did and was equally stunned. I went to the mud flats with Kevin and we gave it the old college try, no more shards but I did get two boots full of seawater.
I was praying you didn't fall over in the mud,
because I would not have been able to stop laughing! I am sure many were watching from the comfort of their homes saying what are those two idiots doing? Good times!
Bad news is that I found only a rock dump (No glass or metal) in the location I searched. Good news However is that I did get permission to metal detect an 1740s house and the homeowner said he will...