Johnstones Leyland decorating centre - scanning a tester pot

[Possom]

I've read here on the forum that it's possible to buy Farrow & Ball colours at Johnstone decorator centres (not the F&B Paints; the colours having been pre-scanned.

I have a sample paint pot from another company (not F&B), and I was wondering if these Decorator Centres can scan the paint colour from the tester pot?

Also, I'd want the colour for the outside of a front door. What "type" of paint (eg gloss, eggshell) should I ask for?

Thanks!