Barbara, since I live in London my message is in Cockney Rhyming slang which, if done properly only the first part of the rhyme is spoken, so here is the "translation"
"Hey Barbara, if you show your boat(Boat race=Face) in the Smoke (long standing slang name for London )we'll get some pigs(Pigs ear=Beer) in (well, enough for a tumble(Tumble down the sink= drink), anyway)and have a knees up (Knees up as in "Knees up, Mother Brown= a dance or London equiv of a Ceilidh), Let us know if you can in advance, Your China (China Plate= Mate, friend, Buddy), Micca" hope to see you if you get to London, Micca