I have just added this to the UK Map of places to fly your Drone at https://dronescene.co.uk
Filmed on a Saturday Afternoon, very much an open space where one can fly maintaining a safe distance from other elements. Not a lot of people in the park but not completely quiet either. Good place for test flights, wouldn’t recommend flying too high here though due to neighbouring roads and construction.
Must follow Dronecode at all times.
Hi Harshit! Welcome to GADC! 
If you haven’t already, take a look at the Map of Members. This is a relatively new feature so not everyone is on there, and I’m sure there are far more members in your neck of the woods that will come and say Hi.
(Don’t forget to add yourself to that map : Members’ Location Map - A Guide)
Who would I need permission from to fly there on Sundays?
@wavewasp - I have only even flying there on weekdays when it’s not busy and haven’t really required any permissions from anyone since there aren’t people around and it’s quite open. However, I can imagine a Sunday being more crowded with dog walkers or runners. As far as I know it is linked to Peel Park but doesn’t have a society like the Friends of Peel Park so it’s kind of hard to point out towards the right direction. May be the authority for peel park would be able to point it out to you?