It must have been a same-sex marriage, Eddie. Civil partneerships are not available to mixed sex couples.
Sorry, I don't know the answer to your question, JDW, but this made me wince:
"...and we have upgraded to marriage recently..."
You make your marriage sound like a bank account or a flight to the sun:
"I have upgraded my current account to a premium product that gives me free travel insurance". Or "We were upgraded from economy to business class".
Ouch!