The most obvious workplace etiquette tips that jump out at me are:
(1) Arrive on time for meetings & appointments is non-negotiable;
(2) Don’t just launch into the content of the meeting as soon as it starts, especially if you are chairing it. Take time to greet each other and make a little bit of small talk (usually weather and travel related) before getting down to business;
(3) Be polite: please and thanks you’s are a must;
(4) Maintain a professional tone in emails, and ‘kind regards’, ‘best wishes’ or ‘many thanks’ are popular sign-offs;
(5) Embrace diversity - the UK is a melting pot of cultures, and embracing diversity is not just encouraged, but expected;
(6) A sense of humour is important. British people take great pride in being self-deprecating and able to laugh at themselves;
(7) everyone will be on first-name terms. It’s very rare for people to introduce themselves using their title;
(8) The UK is a tea drinking nation. It’s a good way to get to know people, over a cup of tea, and you’ll definitely make new friends if you offer to make the tea for your team or even just a colleague every so often.