Concluding an Enquiry: SA Legislation: SA Closure Notice Returned
A partial or final closure notice takes effect when it is issued. So even though a notice is returned RLS (Returned Letter Service) you should proceed on the basis that it has been duly served. HMRC has no power to determine that an original notice (and any amendment for SA) contained in the notice was ineffective if it satisfied the rules of service. You must therefore proceed on the basis that the notice has been validly issued.
If a new address becomes available at a later date you should send a copy of the RLS notice to the taxpayer at his or her new address. You should not normally issue a new notice unless, exceptionally, the original is shown not to have been validly served.
When you reissue a notice showing the original date, the 30 day appeal period may have expired by the time the taxpayer receives it. In these circumstances we would normally accept a late appeal provided that they appeal within a reasonable period of receiving the reissued notice.