Most 1/2 id tubes have a 3/4 od. I don't think I've come across any that are otherwise. You'll only need two of the 90' barbs. I assume the rest of you components already have straight barbs installed as you bought them second hand?
OcUK Value 1/2" 90° Angled Rotatable Fitting - Black Nickel *2 £6.72
OcUK Value Tubing PVC 1/2" UV-active blue *2 £6.72
Sub Total: £13.44
Shipping: £3.88
Total Vat: £3.03
Total inc Vat: £20.35
Ok thanks
shall I use my 1litre of Nanoxia Stark? I'm guessing that's enough to clean pump out with and then use to fill pump up with ?