Probably too late for some, but...
Meadowbank Terrace is closed for roadworks. The East end of Royal Park Terrace is also closed. And so is the bottom of Queens Park Avenue.
So, if you want to go to the park from the east, you probably need to go via London Road and either cut back down Abbey Lane, or down Abbey Mount.
PS Roadworks will continue for a few weeks, but only during working hours.