For anyone interested, this is now sorted, though only a change of throttle bodies sorted it (had an old grubby set knocking about). Disconnecting the throttle cables done nothing, as did connecting the pipe to the air sensor or swapping the ecu, same issue each time. Something on the throttle body unit wasn't happy, throttle position sensor perhaps or something?? though the factory markings hadn't been moved (by the look of it). It likes it old grubby one's anyway so it's all good!! cheers!!
