Cup and bearing brackets the quality is entirely in the servicing, if you don't service them then they get loose/dirty/ect and that causes issues. The upgrade to a sealed unit is a polite way of doing it instead of just telling you straight that you don't look after your bike(s).The bikes are fitted with cups and bearing bottom brackets not Shimano. The dealer suggested fitting a Shimano cartridge bearing for £42. I did NOT expect an upgrade from Kudos but felt they did not live up to the 'top quality' and 'Shimano gearing' billing.
I'm going to take a guess that it's £42 as they are ordering the most expensive thing they could get to make sure you won't come back again saying it's inferior to some parts you imagined.