HI Robert,
As Tommy3917 says Poundland or equivalent are a good source. Also the net bags that fruit and veg are 'packed' in. it depends of course on the scale but I have found many colours and mesh sizes this way. For floats or weights think of craft shops. You can get various sizes of polystyrene balls, beads and wood balls. Fishing tackle shop or car boot for small lead weight - but remember lead must be painted (best with two part epoxy)to avoid polution.

HI Robert
Try The Model Dockyard there in Truro Cornwall

HI Robert pound land do a black
Ra ra skirt its nice fine netting, suggest you get a female to buy it, I got some funny looks ha ha

HI Robert just had a thought you could red,pink,orange ,fishing bead for the floats, maybe
Regards lee

HI Robert
I'm not sure about the netting, but how about split shot lead weights for the floats? You could paint them to suit. Regards, Edward

HI Robert have a look on eBay for net there was a bloke who sales ready made nets or you could buy the material from him and make your own for the floats I'm pretty sure that you can get them from there to. Hope this helps, regards Lee.