I tried a variety of setups and always found having the heater the last thing before the hose reel worked best for me.
A few years back I ordered a few L5 heaters direct from ecotemp in America - I bought 3 at once (One for me, one for my dad and a spare) and got them much cheaper that way (about £60 each),.. also because I bought direct I was able to request them without the 20 minute cut-out,...