There are three Credit Reference Agencies (CRAs) in the UK - Equifax, Experian and TransUnion. All three are dedicated to collecting information on your financial behaviour and how it has impacted your score.
CRAs must share your credit report with you if you request it. It’s good practice to look at all of your credit scores on a regular basis so you can keep an eye on any changes.
They all have different scores but this is completely normal. You can get to know your credit score better with free credit reports at ClearScore, TotallyMoney, Credit Karma and Experian.