You mean so that the only charge is RL's 0.4% on the relevant funds (and maybe subject to some minimum transfer or ongoing contribution amount)? And no other charge?
How would the execution only broker make any money in that case? Unless you mean that they get some other "out of hand" commission from RL? I would expect an intermediary to add something on to the base AMC or charge a fixed fee up front in most or all cases.
Are there any brokers or financial advisers who offer the Royal London PRSA on an execution-only basis, and who charge an initial flat rate set-up fee only? I would prefer this to an ongoing annual broker charge of circa 0.25%, which adds up to tens of thousands over time.