New Cromer purchased 4 Ex RN leander class frigates in the 90's as a stop gap measure to cover a dire hull shortage when most of New Cromer's frigate force was tied up on other duties. the 4 ships bought were the RN Sea wolf converted ships and were used as escorts for carriers while the larger more capable frigates were used elsewhere.
in the 2000's the ships were proving a nightmare to keep operational but even with the arrival of the 4 EX RN type 22's in 2013 the additional hulls were still found busy chasing down pirates, people smugglers and etc off the african coast. new ships were needed add the this the removal from service of the Exocet and the Sea Arrow missile on New Cromer's Type 42 as a cost reduction as the navy wanted to have just one ASM Harpoon.
the loss of Exocet and the lack of a gun severely limited there usefulness, however there ability to operate Helicopters and a ships boat meat they were still decent anti pirate and smuggler vessels. but a new ship was needed enter the BAe Corvette design. her main roles will be to replace the 4 Leander on these anti piracy and smuggling but have the additional punch of Harpoon if called on to do other missions. they are to be more capable that the River class OPVs but cheaper and less capable than a Frigate.
a final tweek..... offering rudimental short term maintenance facility's for helicopter operations. Phalanx is shown but initially the ships will be fitted for but not with.