On the ramjets: The ignition system was on for the whole flight if I recall correctly - it definitely switched on 2 seconds before the boost motors. The fuel pump controlled the amount of thrust by throttling them back a set amount to prevent flame-out, and that was controlled by the Incidence Switch.
The Incidence Switch is located on the end of the radome (that silver thing) and was simply a cone of aluminium that could pivot in any direction, with a contact ring inside. Airflow would keep the cone central except in the case of extreme pitch or yaw, when the contact would be made and the missile would slow down and stabilise itself.
The launch sequence would be something like this:
0 sec - trigger is pressed by Ops, ramjet igniter switches on, protective covers blown off
1 sec - ramjet igniter still burning, internal battery triggered
2 sec - boost motors triggered and missile leaves launcher
3 sec - 485mph
4 sec - 973mph ramjets delivering thrust
5 sec - 1,460mph boost motors finish, ramjets accelerate, wing locks disengaged
6 sec - onwards - missile turns towards target, most maneovering is done early in the flight
The guidance was semi-active homing. The target was 'illuminated' by the ground radar (continuous wave, not pulsed) and the missile dish inside the radome locked on to the reflection before the launch.
The Controller inside the LCP (Launch Control Post) would analyze the target and choose one of four Modes to set the missile into before launch. This depended on his assessment, but also could be changed in flight, if for instance, the enemy switched on a jammer, then that would be targeted.
The dish itself was quite ingenious, having a dipole antenna in the centre with a motor which spun it rapidly at
variable speed This was a crucial part of the anti-jamming design. The dish was moved by two hydraulic rams, and when in flight, the missile 'followed' the dish.
Steering was achieved by hydraulically-powered moving wings.. the tailplane did not move, it had a fixed upward angle of 0.5 degrees, so the the 'bird' always climbed. To change direction, one wing tilted down, and the other up, to dive or climb both wings moved together.
All of this was achieved using transistor technology (no chips in those days) and the LCP had a computer with magnetic core memory!
----------------------------------------------------------------------------------------------------------------
I will get all my notes in order one day, but the main thing was that Bloodhound was a System, not just a missile - there were radars, launchers, control posts, servicing facilities etc. The whole thing being a true RAF Squadron, except for the fact that the birds didn't fly unless Russian bombers appeared on the horizon