am on my second-last block of Grandma's Country Album II

need help with a picture of the Laurel Wreath block, am having LOTS of trouble placing the heart vine applique evenly in the centre in the block

Are you using bias binding or did you straight cut it? Or is just centering the factor? If centering is the factor, then I would measure down from the top and up from the bottom and pin both end pieces in place the then finish shaping the 1/2 heart on the one side.

I cut the vine on the bias, and used my trusty bias bar to make the "stem" the problem is that it doesn't seem to be centred on the block

need a picture to see where it needs to go, hard to place an irregular shape like a heart properly

and the actual pattern doesn't have a block-sized picture I can trace or set the vine over and pin in place....

you can't find the center of the piece to be appliqued because of it's unusual shape?

I'd put the piece on a piece of paper and cut a square that encompasses the entire thing. Then fold the square in quarters giving you a "center". Put the appliqued piece back on top of it and pin the center. Then put the center of the applique on the center of your heart. Will that work?

yes, that's the way I would do it.

After looking at the block again, I would applique your 2 bottom cornor appliques first. Then you'll see how far they go into the block and it'll then give you a better visual where your heart needs to be placed to be centered and then draw the heart on in pencil lightly and place and pin your strips.