How can I tell if I need new fuse box with rcd?

Yes this is correct as its a requirement of BS7671:2008. The wiring regulations were extensively revised in 2008 and now require that RCD (electric shock protection) is fitted, even if only small changes are made to the wiring. As the other reply has stated, the work must be carried out by a registered person and the work notified to building control under Part P of the building regulations. If the kitchen/bathroom fitter can not show you their registration and/or ID then you would be advised to get other quotes from NICEIC registered contractors.

It is generally the way to go if your board is not protected. If they are quoting in the region of 400 to 450 for the board (5 or 6 way) inc uprating gas/water bonding, main bonding and main tails. you may need to contact your service provider to fit a 100A isolator. Also you should ask for the details of the fitter so you can check they are on the approved register which you can check on line. The national on line register for checking goes live on 30/06/14. You can check their registration on the Registered Competent Person Electrical mark and website. http://www.electricalcompetentperson.co.uk/ If in doubt you can always use your own electrician to fit a new consumer unit. I would advise that if in doubt you get quotes from a NAPIT registered contractor. I know that they are checked annually without fail for their knowledge and compliance with regulation.