Sorry Terry, I've no idea about the planks - but then I'm only a WCCP volunteer once a month and wouldn't expect to hear what the EA are up to anyway. I must admit it does seem odd to have what appears to be a rubbish trap installed and then not actually retrieve the rubbish, the accumulation of flotsam looks ghastly, worse than if it had not been installed. I just want to get in there with a pole and net!
Most likely the planks were installed as a perching spot for birds, the accumulation of rubbish there being an unfortunate side effect, hence no apparent plan in place to clean it.
You are right in that we will not be retrieving any rubbish until Spring next year as we are not allowed to get in in case of disturbing the trout spawning. For what it's worth the WCCP are not allowed to touch the vegetation and are only allowed to clear rubbish, conversely the EA only deal with vegetation.
There was a brief news report on BBC about the EA work, but I couldn't find anything on the EA website unfortunately.
http://news.bbc.co.uk/1/hi/england/kent/7695771.stm