If you do blank the EGR, to cover the legality, its worth pointing out that " It is an offence under the Road vehicles (Construction and Use) Regulations (Regulation 61a(3))1 to use a vehicle which has been modified in such a way that it no longer complies with the air pollutant emissions standards it was designed to meet. Removal of a DPF will almost invariably contravene these requirements, making the vehicle illegal for road use.
A vehicle might still pass the MOT visible smoke emissions test, which is primarily intended to identify vehicles that are in a very poor state of repair, whilst emitting illegal and harmful levels of fine exhaust particulate."
The MOT testers don't usually check the EGR, they just measure emissions. Blanking the EGR has often reduced smoke/emissions, so there's no real need to check the EGR.
Technical questions and answers about the Mazda Bongo