If it's the Yorkshire Hornsea Mere Ron, never fished it, but once fell in from a rowing boat whilst staying at the Wakefield Schools Camp in the 50's.
I still remember the first meal I had there, thick chunks of dry stale bread and OXO from an enamel mug.
I hated every day of the three weeks spent there. I collected enough fossils from the beech to fill a museum
I can remember the exact period, it was when Don Cockell fought Rocky Marciano for the World Heavyweight title, lost 3p on the fight. Also had my first fight there, under the centre light in the wooden hut we slept in. Roger Gelder I think was the other lad - went on the be best mates.
He had his head up my arse forgood a few years after that, I played at prop forward, he was second row.
Took a visit back last summer, the place still looks like a prisoner of war camp.
From reading the info on the board by the Mere it's produced some good fish, including chub.