Patent dating guide
This date is later than the date on which a patent was granted see 18.86, 24.01, and which is the date effective for all provisions of the Act prior to s.25(1).
This was confirmed by the Hearing Officer in ITT Industries Inc’s Application  RPC 23 (see especially page 27 line 20 onwards).
There is thus an interval of several weeks during which the provisions relating to an application have ceased to apply but those relating to a granted patent do not yet have effect.
For example, since s.19 is a provision prior to s.25(1), an application cannot be amended once a patent has been granted, but the specification of the patent cannot be amended until after publication of the notice of grant, because s.27 is a provision subsequent to s.25(1).
If the comptroller is not notified of an address for service for the proprietor of a European patent (UK), then the proprietor’s address on the register will be treated as the address for service even if that address is outside the United Kingdom see also 77.05. Where a European patent (UK) has been revoked by the EPO Board of Appeal and is subsequently restored by the Enlarged Board of Appeal following a petition for review under EPC Art.112a, any renewal fees which fell due whilst the patent was revoked are payable within a two-month period following the restoration. A certificate of payment will be issued once the fee is received and/or a report detailing errors if the payment is incorrect.
Engineering Plans (3,000 items): Drawings, made 1837-47, of patents granted between 17, with accompanying name and date list. This section specifies when a patent begins to have effect, how long it may continue in force, and what must be done to keep it in force.Further requirements concerning renewals are set out in rr.36 to 39 and 41.Most original patent records were destroyed by fire, December 15, 1836.Reconstruction of the records was authorized by the Patent Act of 1837 (5 Stat. Copies of specifications relating to numbered patents, 1837-40, and to reissued patents, 1838-48.