As the website does more than the old app, and works just as well on mobile devices, we have decided to retire the old Android and iOS app. You can still add an icon for the site to your mobile device so it looks and acts much the same as an app though.
Choose the right page
In your web browser, you should go to the page you want to start on - probably main page of the site, although you might want to jump straight to your account or the advice centre. There should be an option called Add to Home Screen on most mobile devices.
Android phones and tablets
On Android devices, including Samsung 'phones that use the Samsung Browser, the menu is three dotted lines at the top right of the screen. If you don't see the bar along the top with the menu on it, scroll down the page, then quickly scroll back to the top and the bar should appear.
This menu should have the Add to Home screen option - it's about the fourth one down on the Samsung browser, and about option nine on the Chrome browser used on other 'phones.
iOS (iPhones and iPads)
On current iOS devices (iPhones and iPads) you need to click on the icon that brings up the sharing menu, which looks like a square with an arrow coming out of it.
On the third row, next to options like Add to bookmarks and Add to favourites, is the Add to Home Screen option.