Does my Wylex NHRS6604 fusebox need replacing?

You may need to add RCD protection as you may not have this on socket outlets

I Would’ve thought the fuse box would needed changing to date

That consumer should not need replacing but it would be easier to assess if a picture of fuse box was available or the reason why the electrician recommended it to be changed, also different standard for rental purposes.

If your electrician recommended a replacement for your Wylex NHRS6604, it's important to consider their professional opinion. Electrical components do age, and advancements in safety standards may have occurred since the installation in 2004.

If you have concerns or doubts, it's advisable to seek a second opinion from another qualified electrician. They can provide a thorough assessment, considering your specific situation and ensuring that your electrical system complies with current safety standards. Regular inspections and maintenance of electrical systems are crucial for safety in your home.

There it’s not legal requirement as long as it’s good condition and pass all electrical testing or house was not upgraded within new circuit

Wylex NHRS6604 Is not compliant wit latest UK electrical regulations.
Fuse box must be metal instead of a plastic one.

A fuse board does not need to be replaced due to its age. If & when the installation undergoes an electrical inspection & test, it is then found to be non-compliant with the British Standards' minimum requirements, then & only then will it need replacing. C. I Builder Company

Unfortunately you probably do need it to be replaced due to changes in regulations. It is unlikely that your fuse board will be fitted with the correct safety devices (RCD's and SPD's ) to keep you safe if a fault did occur.

Due to the changes made to the BS7671 in 2018, a lot of electricians instantly assume that a consumer unit made of combustible materials is not compliant. This is not necessarily the case. This would only apply if there is any thermal/heat damage to the unit or if there is any access to live parts on all sides of the unit. Additionally it would also depend on the location of the unit, ie above an escape route or under an escape route. I hope this helps. If you have any questions please feel free to contact me.