consumer unit?

Yes I know its not a switch or a socket but the only elecs catagory:
I have seen Wylex plug in MCB fuses to replace the wired type fuses in my Wylex consumer unit I know they will stick out a bit but won't be in the way or get knocked: is the a 'For and against using these in my Wylex c.u.?

Had it all checked before moving in and all including the wired fuse consumer unit was safe but advised to update for ease not for reasons of safety.
Had offer last year Feb for free visual check from a contractor working for our supplier. Testin was a joke polarity test on two sockets then declared wiring ok. [I know it is]. Eyes lit up like organ stops seening the 1970 wired fuse consumer unit. Condemed it as dangerous [it's not it was teste by my mate who is a tester himself] Quote for £810 to change to MCB said it would only take half day so we won't be without elecs for long.... but out of pocket instead. I've seen same unit ranging from £36 - £198 on a range of 4 -12 way units. Is this a Part P rip off or what???