Yes you can blank off the EGR valve - many do. If they are going to remap the vehicle this should be a good modification.
At the moment it is classed as engine tampering and big brother does not like you doing it although you should be fine at MOT and that is all that matters really.
I don't think it's a good idea to map the EGR out . A) it was designed that way. B) It's lasted 120,000 miles so far with one c) it's now illegal to have a non - functioning one and an MOT fail if they work it out, and d) It's there to keep emissions down. I'd rather people kept their vehicles in proper working order and didn't pollute unnecessarily thanks very much. I make the effort to, why shouldn't everyone else?
Oh, and a good remap will cost you nearly double what replacing or cleaning the EGR out will. Will you have the car in another 120,000 miles or 7 years?...
I have no time for people who's only suggestion of a fix to others is to make their vehicle illegal.
I have no issue with remapping for power or economy gains, but making a vehicle illegal and possibly more polluting instead of fixing it properly is a poor way out.
2004 Multispace Desire HDi - "Bertie"