If it's really banned then there's no way you can access the site but you said you can access it freely without any restrictions whatsoever? Then I think that is a good sign that the banned have been removed already. I won't advise you to use a VPN as that can only cause you a problem as some platforms won't allow such tool.

I noticed that some comments here talks about how risky it is to use a centralized exchange because it can hold your funds but I think that wasn't the main concern of the OP here plus he is doing a trade and it will be a hassle if he will just pull out his funds every time he do a trade. Another thing is that centralized exchange are the one that is used the most by traders, maybe because it has a better feature/functions than a dex.

BCC is only a few days old. It might take a few weeks or months for decent software to be developed and bugs to be worked out.

You can always just save/write down your private keys and reclaim your BCC at a future date. In 10 years from now BCC might be worth millions and segwit(fiat)coins might be worth pennies.

Pretty sure you can sign up to Poloniex and other exchanges and it shouldn't be a problem.  Most sites which handle US customers will accept UK ones as well unless it's something solely based around dollars rather than other currencies (in Poloniex's case there's no fiat involved so you should be good to go).