Funnily enough I installed a 12V DC TV in mine last weekend. I've used an in-line fuse and a switch (with a sufficient amp rating) to wire it direct to the leisure battery and to be able to turn it off completely so as not to drain the battery. I had a chat with some leccy chaps at work, who didn't see an issue going direct to the battery, but I still checked using a multimeter before final hook-up, all seems well with it. I'm happy to hear other's thoughts as I'm not an expert!
I've used a cheap freeview antenna from eBay, which is fixed to the "fake" window behind the cupboard. As the glass is heavily smoked, you can't see it unless the sun is directly on it.