Don't call the 0844 number they want you to use. Use 01244 572300.
Check, and properly read, their T&Cs before signing up for one of their accounts. They charge quite a lot to provide an account to people who already have a bad credit record.

FCA regulations effective 26 October 2015 require banks, card companies and insurers to use an 01, 02, 03 or 080 number for existing customer contact.

If a premium rate 084, 087 or 09 number is being advertised, complain to the FCA.

sam67 wrote on Nov 14^th, 2016 at 1:37am:

Don't call the 0844 number they want you to use. Use 01244 572300. Check, and properly read, their T&Cs before signing up for one of their accounts. They charge quite a lot to provide an account to people who already have a bad credit record.

They seem to suggest they are an Authorised Payment Institution.  More details about them here

In the FAQ's they mention business accounts, so I am unsure what market they are aiming at.