The lean to is the reserve option in case the plumber / kitchen fitter decides it wont fit when they get involved, in that instance the lean to would go where the lpg gas cylinders are currently situated so that would still be close to the main pipe work inside and limit the pipe work runs externally.
Just got to wait for the kitchen to wear out now, its 13 years old but still functional and looking good to me and SWMBO wants the kids to be older before she gets another kitchen so it could be some time - gives the relative technologies time to mature I guess and some minor insurance against government U turns on strategies not that i tend to lean on their every word !
Moxi