I know an ETF that I would like to buy, but how do I actually invest in it? E.g. what are the steps I need to go through, which organisation to contact? Can I buy through a bank or do I need to directly buy through the stock market. I need enlightening! I'm UK based.
Usually, you can buy ETFs through brokerages. I looked at London to see if there's any familiar brokerage names, and it appears that the address below is to Fidelity Investments Worldwide and their site indicates that you can buy securities.
Fidelity Worldwide Investment 25 Cannon Street London EC4M 5TA United Kingdom
Any brokerage, in theory, should allow you to invest in securities. You could always call and ask if they allow you to invest in ETFs. Some brokerages may also allow you to purchase securities in other countries; for instance, some of the firms in the U.S. allow investors to invest in the ETF HK:2801, which is not a U.S. ETF. Many countries have ETF securities available to local and foreign investors. This site appears to help point people to brokers in London.
Also, see this answer on this site (a UK investor who's invested in the U.S. through Barclays).
First of all, you'll need a securities account. Nowadays, most large banks offer this as a standard product for all their customers, though it may require some extra paperwork.
Then you need to buy shares in the ETF. This is indeed typically done through the stock market, but there are alternatives. Some banks will sell securities to you directly, but usually only those they create themselves (options and such). Some also offer ETF investment plans that allow you to buy shares for a fixed amount each month through the bank.
In any case, the bank's online banking interface should support all these options.
However, fees are an important consideration! With some banks, the securities account is free, others charge an annual fee. And the fees on stock market transactions and investment plans also vary considerably, so it could be worth it to consider some alternatives.