Had same problem with my 2.0 TDCI 05 plate 100,000 miles. Took the EGR off , no blanking plate. Light will always be on the dash BUT it will pass MOT NO PROBLEM because they put there foot down to rev the car up. JUST had mine pass 2 weeks ago with the EGR OFF.
CAR would only go 50 max before. GOT THE INFO OFF HERE, a bloke who worked in a mot garage.
TAKE THE BLANK OFF.