It is entirely permissible on all airlines except those under the CAA - those with "G" registered tail-fins!

Unfortunately, the CAA and the DfT lag way behind everyone else.

Yes - it's very important to know where the exits are but unless you're partially sighted or blind (in which case the crew will give you a separate briefing and till you whether to go forwards or backwards and how many seat rows there are to your nearest exit) you are perfectly capable of following the video and the safety card and working out where things are for yourself.