The 135 T2 is very nice and I'm sure they will be very pleased with it. One question, do North Midlands IR their pilots? I ask only because the blurb says "operating over the Peak district in the dark" and mentions the ILS and autopilot for recovery in the event of inadvertant IMC. The autopilot and the EFIS screens in the 135 are great BUT it is quite a complex little autopilot and you can easily tie yourself in knots unless you are very conversant with what it is doing, what you are asking it to do, and which bits are engaged/disengaged.
For what it's worth, I think if you are operating away from decent cultural lighting ie somewhere like the Peak District at night it makes it a whole lot safer to have an IR (this implies no criticism of the abilities of the guys at North Midlands, before anyone leaps on me, I just think if you have an aircraft that has the capability then you should be given the training to let you use it to the full to enhance the safety of the operation).