Paper tax return - enter 0 or leave blank?

Astronought

Unfortunately because of her mother's death last year, my wife has had to register for self assessment to report the details of a Chargeable Event from an offshore life insurance policy. We're now filling in the paper tax return (as she cannot use the default hmrc software for her particular return) and we're not 100% sure on what to enter onto Boxes 43 to 45 in the "Other overseas income and gains" section on the SA106 'Foreign' page of the return.

Well that's not quite true, we've figured the Gain and Number of Years from the certificate will simply go onto Boxes 43 and 44, but as the certificate says that "This policy has not suffered tax at source (with the exception of some non reclaimable withholding taxes on some underlying income) and the policyholder will not be treated as having paid Income Tax at the basic rate on the amount of the gain in accordance with section 547 (5) (a) of the taxes act" do we enter 0 into Box 45 (which is where 'Tax treated as paid' is to be added) or do we leave it blank?

The notes say to use the certificate to fill in Boxes 43 to 45 so at first we thought we'd put a 0 there, but doing some googling brought up an Abrdn technical page that would seem to imply that instead of putting a 0 we should leave the box blank, so now we're thinking we should possibly leave it blank.

Now it probably makes no difference at all, but I was wondering what is the proper way to deal with this on a paper tax return, should she leave it blank or should she enter a 0?

Thanks for helping us on what is probably a non-issue but is causing us both some concern as we've never had to do a self assessment before.

Bookworm105

as you surmise blank or zero makes no difference

Pedantically putting 0 is actively declaring zero, whereas blank is silence.
0 then tallies with what your cert says.
But it makes no difference

Astronought

Many thanks, that goes along with what we thought so my wife is going to put a 0 to just underline what's on the certificate.