"enquire if" is a correct and valid phrase in written English.
You can use it when you want to ask for information or ask if something is the case. For example, "We should enquire if the store has the item in stock before placing an order."
Dear Mr Brown, I am writing to enquire if you have any vacancies in your company.
Camilla appeared to enquire if it was the biggest to be found here.
It was just as well no one had bothered to enquire if the change would be for the worse.
I was tempted to enquire if all the much-vaunted species had stayed away along with the American tourists.
When I enquire if he now regrets the idea, his spokesman curiously insists: "There was never a champagne ban.
Intrigued by the name of an estate agent, he calls in to enquire if it belongs to a real person.
An obscure musical gag enquires: if a guitarist and a mandolinist fall off a cliff, who hits the deck first?
The final piece of the jigsaw came in the form of a phone call, enquiring if the museum would like to take custodianship of an old naval uniform.
My aunt usually relates the tale with a mixture of laughter and wounded annoyance, describing how my father walked up to the box office armed with a fistful of crucifixes and when enquiring if she too could have one, he said 'No'.
The interview was brought to a close 22 minutes in by Patrick O'Flynn, the party's head of communications, after Farage was accused by O'Brien of "reverse-ferretting" over a promise to have his EU expenses and allowances audited, before enquiring if Farage would be willing to sign up to a transparency arrangement used by Labour MEPS, which he had to hand in the studio.
Was he enquiring if Mrs. Bath and I planned evenings of violent sex?
