I do fish there myself, so I think I can offer an opinion I've never booked 2 weeks in advance, it's normally just the night before if I fancy going over.
Having 13 lines in the water may go some way to explaining why it wasn't fishing well, I try and go mid-week so it's pretty much only me on there. Considering the size of the water, 13 lines across it isn't the best.
With regard to snagging up in the weed, drop-off leads inside solid PVA bags works for me, especially when chucked into gaps in the pads/weed.
Guy - I'm tempted when I come back up, time to dig the thermals out for a night I think