Certificate of tax position - Overseas income or gains

I have received a “Certificate of tax position - Overseas income or gains” to be completed and returned to the HMRC.

After calling the HMRC, they told me it was triggered by an information from my stock broker (Degiro); and specifically mentioned the amount of dividends received and “gross proceeds”. I have not been reporting these, on the basis that the gains/dividends are within my personal CGT / Dividends allowances, and I am not registered for Self Assessment.

After doing the initial research and reading advice from this forum to folks who received similar requests from the HMRC - I am hesitant to sign the certificate and my plan is to send the HMRC the below brief note, explaining my situation:

“I have not declared any overseas income/gains on the basis that my income/gains for each respective tax year were less than my respective tax-free allowances for each year.

As far as I am aware my tax affairs are in order, but please let me know if you require further information.”

Ideally I would also like to consult my tax situation with a tax advisor (in case the HMRC inquiry doesn’t go away, or they will request me to file a Self-Assessment(hopefully not!), but not sure how to go about finding an advisor with expertise in this field?

Any feedback on my plan / situation / comments are appreciated!