Depends on the company, but typical junior salaries are £35-45k a year, mid level around £50-65k year and senior somewhere between £65-85k a year. Obviously you have FAANG who pay significantly more and finance firms, but they are not the majority, and I've hired or have friends being paid in these ranges who are extremely talented and from top unis.

Upper ranges for all levels accross the very highest paying employees are £100-400k when including bonuses usually. Usually these are quant/quant-dev jobs and FAANG.