KMS1

Thank you Terry, I have only just read your reply as I had been side tracked by other issues. Fortunately in the end I did not attempt to remove the bottle but replaced the two grommets for the two pumps (headlights and windscreen). The leak now seems to have been stopped however I can't be sure whether it was the new grommets that did the trick. I had difficulty removing the rear (windscreen pump), when I replaced it I realised that there are two short stubs exiting the pump and one of the tubes kept coming off  its stub. There is little room to work but I eventually managed insert the pump into the washer bottle without dislodging the tube and all now seems to be well. 
You confirmed my suspicion that the job is not as easy as the Haynes Manual would lead one to believe. Many thanks for taking time to answer my request.