Just make sure your lipstick matches your heels honeypie
And, be sure the, ahem, collars and cuffs are matching as well.
As to the choice of suit, it really does depend on the workplace, what sort of person they’re looking for, what the job is, etc.
Even though it’s in the uncivil service, I’d personally favour the Glen Plaid option out of those two, as it’s a little more “individual”. This is a good thing in interviews as something memorable can help make you stand out a little bit. As long as it’s not an OTT pattern, that is!
Nice, clean white shirt. NOT a brand new one. Stands out a mile when someone has a brand new shirt, straight out of the bag! Nicely worn in, properly ironed.
Now, you don’t mention shoes. If they’re brown, I will hunt you down and kill you. To death.