Northumberland was one of mine. She was one of four I served on. The others being Monmouth, Lancaster and Somerset.
When they were first introduced they were jokingly known as "The Skoda Class" because they had small crews and were seen as cheap and cheerful replacements for the Leander Class they superseded.
The biggest problem with them was that they were originally designed to be 30 day endurance anti submarine patrol ships operating in the North Atlantic but they were pressed into global service in any theatre. Even with modifications, life in hot climates could be pretty uncomfortable.
The original, pre Falklands design had them lightly armed and operating with an armed support ship (that eventually became the Fort Class, George and Victoria). Following the lessons learnt in that conflict, especially from the loss of HMS Sheffield, they were redesigned to include better close range weapons, much better damage control systems and improved command and control.
When they first came out they had a crew of about 170 but various internal compartments were redesigned and by the time they were serving in the Gulf when I was out the in the early 2010's we were squeezing over 200 people onboard. Some having to sleep on camp beds in various spaces onboard.
These hulls are around 30 years old which is a hell of an innings for any ship and a similar service life to the Leander class. The problem as always is that government feet dragging has led to the first of their replacements not entering service until 2026/27.
The sacrifice of keeping two huge aircraft carriers in service has been the rest of the fleet. There are only two of the six type 45's currently at full readiness. Both RN Amphibious Landing Ships, Albion and Bulwark have been sold to Brazil. The three fleet auxiliary landing ships (the Bay class) are all currently laid up. This means we have no operational capacity to move the Marines should the need arise.
Good job the world is currently a safe place.