There's your problem right away. There's no point contacting the Loyalty Dept. they don't reward loyalty.
Here's the email you need foroperationalreasons@p&o.co.uk.
I contacted them to ask them, whilst I didn't have a BLC card, I had just eaten a BLT, and could I get extra OBC as a result. They were very polite but said this didn't qualify, however I have been assured that I am on their mailing list and the For Operational Reasons Department will be in touch should a BLT qualify in the future.
This department really seems to know what they are doing.