When to follow up with HMRC on your application:
Please note, HMRC can take up to 7 weeks to respond to an Advance Assurance or Compliance application. Whilst this is usually much quicker, please wait for the 7 weeks prior to sending a follow up.
The next step would be to check any possible address HMRC may have sent a response to. This would include the registered address at Companies House, with an accountant, your spam folder etc...
That said, if there's still no sign of a reply, there's 2 ways to follow up:
1. By email
The best way to contact HMRC to follow up with your application is by reaching out to the same email the application was originally sent to.
The email address is firstname.lastname@example.org
Please note that HMRC may take up to 2 weeks to reply to email follow ups.
2. By phone
Alternatively, HMRC also have a telephone answering machine. (This is no longer a direct line). You can leave a message, and they will determine whether a call back is needed.
The phone number is 0300 123 3440.
Please note, we generally see that emails are replied to faster than phone messages.