If you want to understand the rational behind the LV network design architecture of the UK, you really ought to have a knowledge of the 11kV, 33kV, 132kV, 270kV, 400kV network architecture, protection etc.
Having spent 30 years as a Distribution Engineer with Eastern Electricity, ending as Shift Control Engineer in charge of the biggest Distribution Network in the western world I must say I have no idea what the 400kV, 275
kV, 132kV, or 33kV networks have to do with LV Network design. LV Network design is basically an exercise in applying Ohm's Law once a decision has been made about the peak current calculated from the 'After Diversity Maximum Demand' (ADMD) of the consumers/customers to maintain the voltage within statutory limits. ADMD will vary greatly depending upon whether mains gas for heating and cooking is available or not. In the mid 70's 'With gas' 2kW was used; 'No Gas' 6kW, 'Electric Heating' was 'Heating Load + 2kW'.
I'll concede that as 11kV/LV transfomers only have off-load tap selection, the maintenance of 11kV volts by on-load tapchangers on 33/11kV transformers plays it part in the regulation of LV volts received by customers but going up to even higher voltage systems is unnecessary.
I've read many textbooks about Electricity Distribution Engineering, most of which are still on my bookshelf, but none deal with LV in any detail at all as far as I can see, other than a bit about HRC fuses, so cannot make any recommendations but I'll be happy to try to answer any direct questions about design philosophy, tapered mains, fault impedance etc...