Help! Police certificate - document number and expiry date?

[starly]

Hi everyone. I was requested to submit police certificate for my study permit. However, there are some issues.

1. I have studied in the UK before. Under the 'Country or territory of issue', there are only these categories for UK
a) UK - British National Overseas
b) UK - British overseas citizen
c) UK - British overseas terr.
d) UK - British protected person
e) UK - British citizen
f) UK - British subject

I would assume these apply to UK citizens which I'm not. What should I do in this case?

2. What should I fill in document number with? My police certificates have no number.

3. What should I fill the expiry date with? My police certificates have no written expiry date as well.

I would appreciate if someone could help me with this. Thank you!