Internet Rule #1: Don't ask medical questions on the Internet
Internet Rule #2: Don't ask personal finance questions on the Internet
Internet Rule #3: Don't solicit investment advice on the Internet
While I am strong believer of all three old adages, in this case I suggest you look for a UK investors Q&A forum to identify a UK-focused app that gives real-time quotes.
Typically delayed quotes are free, real-time quotes are a pay service. Indexes (FTSE 100, S&P 500, Nikkei 220, etc.) are often real-time, at least in their respective countries.
At least here in the USA, if you have a brokerage account, their quotes should be real-time provided you are logged into your account. I use my brokerage's website, their PC-based trading tool, and their iOS app. All three give real-time quotes.
Short-term trading is for people who have the time to pay very close attention to the market. It is difficult to be a successful short-term trader if you go into back-to-back one-hour meetings at work, have project deadlines, etc.
If you decide to do intermediate-term or long-term investing, real-time quotes won't be terribly important. If you are looking at charts with a 1-day period, those are closing prices. Turning off the candlesticks and switching to a line graph will take out a lot of the noise.