Although the lead flashing could/will fall out eventually I can put it
back myself -which isn't too big a job. If the plastic breaks I just
have to start again. However, 10 years is quite a long time and a
saving of 350 pounds is quite significant.

My god! Is this a stepped flashing or a straight line join?

Anything other than proper lead flashing looks cheap and nasty.

Lead flashing is dead easy to do. I really enjoyed flashing in my
conservatory. Although a stepped flashing would be more difficult than the
straight one I needed, I almost wished I had needed to do one as I found the
leadwork really enjoyable. A really nice material to work with. Easy to cut,
easy to bend. Stays exactly where it is told.

Don't skimp on the patination oil, though. I missed a bit, and it is really
quite obvious if you look.

Christian.