Plums can be very slow to show any signs of life, stick with it, if you planted it into the ground this Feb i'd wait a couple more months for signs of life. I almost gave up on mine last year, it did eventually put on a few leaves but this year it looks fab.
As for the bramley I can't help from experience but if it is green underneath then it's alive so again i'd wait a couple more months.

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Always aim for the best result possible not the best possible result

Peanut aka Joanna