Cast your eyes over a savings best-buy table, and you'll find most of the top rates are offered by relatively unknown banks such as Oxbury, Monument and NuWealth.

It is easy to leave your money in a less attractive account due to inertia or forgetfulness, but some might feel these rates are too good to ignore - especially when compared to the paltry offerings from most high-street banks. 

Oxbury has an easy-access deal paying 5.04 per cent interest - far more than 1.66 per cent on Barclays' Everyday Saver, or 1.75 per cent on balances up to £24,999 on NatWest's Flexible Saver. 

So why are their rates so much better, and what should savers check before they take the plunge? 

> Top easy-access savings rates: Find the best deals 

Does my bank have FSCS protection? 

If you are concerned about choosing a smaller bank, the first way to allay your fears is to ensure that the bank in question has FSCS protection.

The Financial Services Compensation Scheme ensures that your balance will be protected up to £85,00, or £170,000 for a join account if your account provider fails.

Checking the FSCS register will also highlight whether scammers are using the name of a legitimate firm in order to get hold of your money.

You can check if your provider is registered on the FSCS website.  

FSCS protection only provides protection for UK-based banks.

Some banks share licenses with each other, especially if they are owned by the same parent company. This means that if you have accounts with firms that share licenses, you will still only be protected up to £85,000 if they both fail.

You can check if your bank has a shared license here.

Why are smaller banks' savings rates better?

Less established banks and building societies generally top the lists when it comes to the savings rates they offer.

This is because they are vying for market share, and so are more generous in their offerings in an attempt to gain customers and build loyalty. High street banks, meanwhile, already have strong customer bases so need less cash from new customers.

What this means for those saving with high street banks is that their interest rate is unlikely to be competitive, while those in the market for a new account could make much better returns with their savings.

Also allowing them to be competitive is their far lower operating costs compared to traditional banks. Without a need for branches, branch staff and ATMs, these challengers can afford to be more generous in the rates they offer to customers.

Check a bank's customer service 

Of course, hand in hand with a lack of branches, comes an absence of in-person staff to help you solve your problems.

For those who value their local bank branch and the face-to-face support you can get from it, switching your savings to a less well-known bank could prove an unwelcome change.

Many challengers use new technology to allow them to offer quick customer service. This is because newer firms are able to adopt and integrate up-to-date technology more quickly than banks that rely on legacy systems.

Unfortunately, this often involves chatbots and messaging, which might not be the first choice for people who prefer a phone call if they can't see someone in person.

Even big banks are increasingly deploying AI chat systems as their go-to form of customer service, though generally you can fall back on heading to your closest branch if you can't get anywhere online.

If you are considering switching, and there is a helpline available, it might be worth giving it a call to see what kind of waiting times you would expect and how helpful the bank's staff are.

Will I get paper bank statements?  

Along with their local bank branch, users of some smaller banks may have to say goodbye to paper statements.

While most challenger banks offer online banking services, as well as apps, some customers might not feel comfortable departing from the way they have banked for years.

Meanwhile, some services, such as popular Chip, only offer app-based banking and don't have an online banking website. This means that those without access to a smartphone would be unable to set up a savings account using these providers.

While some digital challengers are at the forefront of technology and user-experience, other smaller providers such as lesser-known banks and building societies have websites that are difficult to navigate for online banking, especially for those less familiar with the online world.

Before committing your life savings to a bank, have a good look through the bank's website and app. 

Reading reviews of banks on Google, Trustpilot and Feefo can also paint a picture of what to expect when using their services. 

Similarly, these platforms can be useful to find out how their customer services work, and how easy it is to withdraw your funds.