Tim - depends if rowing or or under power.
Thats another issue to consider, row only; power allowed, engine size, lease constraints.
You provide, they provide, electric only if so what thrust, if yours who maintains etc; legal requirements HASAWA, PUWER, Employers liability, tresspassers, environmental issues, anchoring / drifting limits etc, etc its a wonder anyone goes into the fisherey business init!.
I remember rowing a 2-3 man Bewl boat against a head wind when we had run out of fuel not pleasant. A Angling companion likewise at the Queen mum, & seeing a boat swamped at same!.
Might be worth talking to the previous owner of the rights to Weirwood & Ardingly back in the 80's Colin....?. If he's still around, mail me off list for further info.
I would suggest a brain storm with all interested parties, then sleep on it, storm again, run it past the legals, consult with users print the rules & enforce 'em. I know your time constrained but...... get it right now it WILL save you money & heartbreak in the future.
Again all the best in your endevours