Look at levels.fyi, the highest paid E7 is around 250k GBP TC (i.e. base + bonus + shares) and there is one IC6 with 350k GBP TC. But basic devs are in the Glassdoor range, while London is as expensive as SFBA with a much worse weather. Basically a dead-end, like the whole EU right now (technologically finished without a single competitive company after the fall of Nokia).