The PW 206B2 is a flat rated 207 especially for the EC135. I believe you'll find it has a 30 second OEI as will have the TM 2B2.
This is not the case with the latest 902's fitted with PW 207E. I believe it is the PW 207D which has the 30 second OEI capability, which is not fitted to the UK Explorer fleet.