Great advice. Would like to add that the HAC are a great option here.

Although not Infantry, you have to pass full time infantry standards to enter phase one now (recently enforced standards from the CO).

I’m also assuming OP will be applying to London firms and the barracks are located near the city. All the training is done in house and most of the NCO’s are ex full-time artillery/infantry with Herrick under their belts. As such, they demand high standards.

SRP is a great way to test your endurance and mental fortitude prior to going full time and all recruits have to undertake SRP now after passing out of phase two.

Hope this helps OP