Should the UK replace domestic energy billing charges with a fixed allocation of units at a fixed price?

UK domestic energy bills consist of a daily standing charge of around 86p for dual fuel plus unit rates, currently capped by Ofgem at levels that add about £315 a year in fixed costs before any usage. Recent reforms have shifted some policy costs like the Warm Home Discount to unit rates and piloted lower standing charge tariffs, while proposals for rising block tariffs or universal basic energy suggest subsidised rates for initial consumption blocks to aid low users. The idea of a fixed allocation at fixed price would fundamentally alter this by rationing a set volume rather than charging for all usage.