As I mentioned above had my car booked in for wednesday. when i dropped my car off they insisted i should go for a drive with a technician to verify the fault. on doing this he could clearly see the problem of the ridiculously delayed response in D2 several times during the test drive. when we returned they informed me they will need the car for overnight to hook it up to the system etc etc.
when i got there today they told me the software update has been carried out, and the senior technician took the car out for a 62 mile test for extensive examination and coding etc etc. (they completely lost me when they went into the technical details of what they had done). however, i did ask for the updated integration level code which was E89X-09-06-510
On the way back home (unfortunately a short drive) i was so relieved as i had doubts over how effectively the update would reduce the lag after seeing the comments on the US section. although i havent been able to test it extensively, there was no delayed throttle response at all! the car in D mode seems to be a lot more awake and the computer responds very quickly if down or up shift is needed. also the car seems to blip a lot more too.
overall, i am extremely happy with the result as the lag was really starting to get on my nerves and now i can drive around in D mode without fear or embarrassment! as mentioned by DJP it is an essential update. i am going to the lake district this weekend, which will be a better examination of the update, so will post again after the wkd!