The Queen will send a message of
congratulations for the following:
Wedding Anniversaries
60 years (Diamond)
65 years
70 years (Platinum) and every year thereafter
Birthdays
100 years
105 years and every year thereafter
In order to receive a congratulatory message from The Queen it is
necessary to obtain an application form, either by telephoning the
Anniversaries Officers at Buckingham Place on 020 7930 4832 or by
writing to The Anniversaries Office, Buckingham Palce, London, SW1A
1AA. This would need to be returned to the Anniversaries Office no
sooner than three weeks in advance of the celebration date. It is
possible to receive a belated message up to six months after the
event.
There is no charge for this service, but you will need to provide
documentary proof of the occasion.
Further details can be found at
http://www.royal.gov.uk/output/page4893.asp