H.O. Reference number

I'm applying for my settlement visa online, and it asks if I've ever applied to the Home Office to stay in the UK in the last 10 years. I have, but then it says it's required to add the H.O. reference number. I don't have the number anymore, it's been 9 years.

What do I do? I'm sort of stuck.

*Also, it asks if I have been denied entry to the UK in the last 10 years. Do they count 10 years from the month/year, or just the year? I was denied entry to the UK in Jan 2006.

I'm applying for my settlement visa online, and it asks if I've ever applied to the Home Office to stay in the UK in the last 10 years. I have, but then it says it's required to add the H.O. reference number. I don't have the number anymore, it's been 9 years.

What do I do? I'm sort of stuck.

*Also, it asks if I have been denied entry to the UK in the last 10 years. Do they count 10 years from the month/year, or just the year? I was denied entry to the UK in Jan 2006.

You can leave the HO number blank. I always have... or write 'unknown'.

The last ten years is from 10 years ago. To be honest, I would include it, because it would be far worse for them to eventually accuse you of deception or some such.

 Even applying online it allows you to leave it blank? It says it's a required answer.

Another question, is it better to mention my 3 day overstay in the 'additional information' section, or would it be best to write a separate letter?

Another question, is it better to mention my 3 day overstay in the 'additional information' section, or would it be best to write a separate letter?

Either would do.

Even applying online it allows you to leave it blank? It says it's a required answer.

Then write 'unknown'.

One more dumb question sorry, just to be sure I have this absolutely clear.

I paid for my NHS surcharge and booked my biometrics appt. I now pay for the actual visa, go to my appointment, and then for priority processing I pay for that separately, then mail everything out? This was so much more simple 7 years ago.