EICR

Maintenance

I have 6 flats rented to tenants, most of whom have been in situ for several years. The managing agent has in the last week sent me EICR reports, all of which are 'unsatisfactory'. Most of the items rated C2 are relatively minor - eg non-compliant light fittings in bathroom, cracked sockets etc - I have no issue with fixing these. However most of my flats have old style (non RCD) fuseboxes, and these are also listed C2 for each of the flats. This apparently means that I have an immediate obligation to replace within 28 days, for which the total quoted cost exceeds %C2£3000.
My question is: is it reasonable that an old style fusebox in good condition is rated C2 (apparently requiring immediate replacement), rather than C3, which would enable me to spread the costs over a longer period.
The flats are all in old buildings, but the conversion installations were done between 1975 - 1995.