Sorry for the delay in following this up. Not due to lack of appreciation of help given but to desperate shortage of time.
Anyway, the transmission problem disappeared the following day so must have been due to my drowning the wheels and arches when cleaning too enthusiastically, as suggested by Amba. I've been able to read codes via a cheap reader earlier today and the relevant ones seem to be U2100 and U2104, (refer to vehicle service manual?). I cleared these and they haven't recurred so far, so hopefully there isn't an ongoing problem in this area. I presume these are relevant to the transmission blip. The management light has gone out but flashed briefly, which I presume was the following misfire codes being re-recorded. Thanks for your help and interest.
Other codes are P0300, P0302, P0304 and P0306 which I presume is identifying a problem with the 2,4,6 coil pack which I have suspected for a while.
There are three others which I'm not sure about.
P0155 refers to sensor heater circuit bank sensor 1 and P0150 refers to O2 sensor circuit bank 2 Sensor 1. I don't know what this means. Can someone help with a suggested course of action, please.
Finally P0725 refers to 'engine speed input circuit'. Is this the dreaded crank sensor warning?
I'm currently scouring the maintenance guides but any additional expert opinions would be much appreciated.
Cheers,
Bill.