In the UK there are certain things that are a bit different than in the USA, and one of them is the formatting of a formal letter.
In the UK you need to align the return address on the right side, and the subject should be always centered. Make sure you leave an empty line after each paragraph, after the greeting and the closing of the letter as well.
In a British formal letter you have to be brief, be straight to the point and maintain professional tone and style at all times. The letter has to be well presented, so you have to stay positive and polite even if you are writing a letter of complaint. Divide everything in short clear paragraphs, be concise and relevant.
After you have written the letter, check several times for spelling mistakes and grammar errors. If you are not British, make sure that you use the British spelling of certain words, and not the American one, or if you decide to use the American one, don't mix the two. Here is an example: It's theater in US English and theatre in UK English, honor in US English and honour in UK English. Stick to one of these!
Dear Mr. Adams,
It was a pleasure meeting you during the conference yesterday. I was happy to be introduced to someone who has made such progress in the field I am working in. Renewable energy is the answer to the future, and sharing ideas and experiences is always a privilege.
As we discussed during that talk, having you and your team over for a meeting would benefit both of us. Meeting your whole team in person would broaden my knowledge and understanding of your aims, and it would make me see in what way I could help your organization.
I will be looking forward to your call on establishing a meeting time. I can be reached any time at 344 556 733.