As far as the original layout is concerned, (showing an over current device instead of just loads) this would be considered as an unconventional circuit as far as BS7671 is concerned. Another example of an unconventional circuit would be the ''Lollipop Ring Circuit, again perfectly acceptable providing it meets certain criteria. So providing due care and attention has been applied in the OPs design and installation it's perfectly fine if maybe not ideal!! Unconventional circuits are permissible under BS7671, if the designer can substantiate by calculation and method, etc. Our American (and even some of our European) friends quite often apply this type of distribution circuit.
The problem being with all the critics here is, that many here need an actual Reg No, to put against any specific, or they become flummoxed, or totally flummoxed. The Reg's are not a step by step guide, or a ''How To-Do book''!! That's not what the Reg's were ever intended to be, they actually require a reader to hold a good basic knowledge of electrical work and theory!!!