Rather than listening to why a web design company makes the fastest websites, it's actually quite simple and easy to test them out for yourself.
There are several speed-testing websites out there. The most popular one is Google's PageSpeed. This service offers you the ability to plug in any website address and see how fast it takes to load. Do keep in mind though, that Google PageSpeed's servers are located somewhere in the United States, so they won't accurately reflect your local loading times if you are located in East Yorkshire or anywhere in the United Kingdom.
There are some other services like GTMetrix that can measure speeds directly from London, giving you a more representational loading time. The default GTMetrix testing location is set to Vancouver, Canada. It requires you to set up a user to change it.
If you're doing business in the UK, it would be wise and worth your time for you to do the following:
- Grab the addresses of the two web designer's websites (or better yet - visit their portfolios and grab the address from one of their clients!).
- Head on over the GTMetrix and create an account (as far as my experience goes they won't send you any spam).
- Once you're logged in, click on the server location below the URL bar until it says London, UK.
- Plug in the address one at a time and compare the LCP ("Largest Content Element" - that's basically the indicator of how many seconds a person waits before they see your website).