Diverter Handset supply hose ejected from unit

My daughter has had exactly the same problem as the one David Hobbis posted a couple of years ago. I took her diverter valve to The Shower Doctor this afternoon and Barrie Seabright kindly had a look at it for me. He discovered that there's a hidden grub screw that locates in the slot on the elbow. This keeps the elbow in place. The bad news is that to get at the grub screw to tighten it up you have to take off the back of the diverter valve (unscrew a grub screw at the bottom of the body) then pull out the blue plastic bit, then unscrew the bolt holding the white plastic core in front of that. The lever then just falls off the front. Now pull off the silver front cover and hey presto the offending grub screw is at last revealed. Insert the elbow and tighten the grub screw. Apply silicone grease (available cheaply from The Shower Doctor) to the o-ring seals and reassemble. NOTE: you do NOT have to dismantle the valve lever in any way. You WILL need some decent Allen Keys to do the job.