Compass is the membership system for The Scout Association (TSA) and contains the records for all Adults after a relaunch in March-2016. It's predecessor was an on-line system called MyBackpack. Records were imported from My Backpack to Compass and it was fraught with difficulties that have slowly been corrected - some errors may still exist so you are advised to get logged in and check your data!
Adult members can request an account to look at their own records by registering for an account. You will need to know your membership number and the e-mail & address that exists on Compass already (validation checks).
A new website dedicated to How to use Compass has been launched and provides very detailed instructions on how to deal with all the things the system has available. You can take a look at what there at this link: Compass User Guides