The 20 min cut out can be a pain in the arse
I use a pole tap but find by 1 pm  when you
Turn the tap of and on it takes a lot longer 
For the pressure to build up and reset its self 
Due to the hose being very flexible and expands  
So takes longer to reset/ some times doesn't 
Then after the 2o mins it goes of but you don't 
Find out till 6-8 mins later when cold comes though 
Then takes 6-8 mins to get hit though again
If you get what I'm rambling in about well done  :

I'm told the timer us really easy to take of
But I ain't done it on myn as it ain't myn 
This is all that corewoods have done to the L5