Considering that the EGR system is intended to LOWER emissions and that your engine likely has an O2 sensor on the exhaust, I can see a couple of problems that you may encounter by blanking off the EGR.
Firstly, because your car will be measuring O2 levels in the exhaust, the PCM will be looking for pre-determined levels under EGR valve operating conditions. If the O2 levels are not what it expects, it will throw a code and put your SES light on, which, of course, is a MoT failure.
Secondly, if your emissions are already at a level which has resulted in a MoT failure, I very much doubt that blocking off the EGR will have the impact that you are looking for.
I have my EGR blanked off, but I have the 1.8 TDCI engine which does not have an O2 sensor on the exhaust - and so doesn't throw any codes, but I have also rebuilt my engine (following a cambelt failure) where I fitted brand new pistons and valves, along with a brand new inlet manifold, and the first MoT I had following the rebuild, the tester remarked that my emissions were lower than he has seen on vehicles undergoing their first MoT.
To be fair, I'm not a fan of EGR systems, as they generate a lot of soot - especially in Diesel engines, and can increase fuel consumption