there are all the rs part numbers and prices:

1 x 389-9114 - £18.35 - G1/4 Norgren pressure relief valve.
1 x 122-655 - £16.20 - G1/4 Norgren pressure regulator.
1 x 384-7666 - £16.78 - G1/4 Norgren inline non return valve.
(above all necessary)
(below - you can either use these or beg, steal or borrow other suitable bits - as rs can be expensive for consumables)
2 x 123-923 - £2.53 each - mouting bracket.
5 x 299-4109 - £0.94 each - elbow.
5 x 299-4058 - £0.51 each - stud.
1 x 386-6207 - £20.96 - 30M roll of 6mm tube.
10 x 419-8123 - £0.44 - push in equal T.
5 x 210-0679 - £2.88 each - straight stem adaptor.
5 x 830-659 - £1.25 each - straight male adaptor.

drawing to follow