yes i know its normal but i have never had them stick as badly as on the mx5 and i have had a veriety of cars now
this morning i really had to jolt the car to get them unstuck. what is the compond of the standard disks as they seem to be made from rusty glue 
soooo also whats best disk and pads to replace them with as they are getting low anyway its a euphonic so its the big brakeson it
muchas garcias
Mike
Welcome to the forum Mike
The MX5 is generally not too bad with this in my experience. To the best of my knowledge my car has Genuine Mazda (Big Brake) Discs & Pads all round, and the only time you notice it as much more than a noise is when I’ve washed it.
The best solution is to try to park it when they are not wet, or as wet, so ensure that you are breaking when you come to a halt, rather than just letting friction/gravity do its thing.
Also, depending on where you park, you could also park with the handbrake applied less (or not at all), with the car in gear.
I’m going to have to replace my front discs, and pads all round soon, and I’ll be going with Genuine Mazda Discs, and EBC Greenstuff, or possibly Redstuff (all available from MX5parts)
I’ve found that Big Brake components are a lot harder to come by, so your choice of sellers is a little limited.
previously its just been a noise and a slight clunk this morning it was like driving with the handbrake and front brakes still on i had to check a few times that the handbrake wasnt still on then BANG i could move.
and even after driving 15 miles in stop start traffic the discs dont seem to have cleaned up any 
I have never washed the car so the only stuff its ever come into contact with lately is snow so id image that + salt and then been parked for a week really didnt do it much good
will have to park it in gear with the hand brake off for a bit
when looking round i was finding it very hard to find anything for the big brakes it seems silly for mazda to fit such a rare disk pad combo to the car both front and rear !
MX5parts are at least reasonably cheap though, so it’s not like you are being forced in to paying ridiculous prices, which is something to compensate for no choice.
But, they are at least better at stopping
they are reasonably cheap im just used to much wider range of friction parts been available for my previous cars it just seems odd when the mx5 is such a sucessfull car
Fortunately my Roadster is parked in the garage with the hand brake off at all times but, my RAV 4 that is parked outside in all weathers does the same as yours as far as the brakes are concerned. After the cracking noise tho they are OK.
i think im going to go for the axxis pads and standard disks should be good enough for fast road and everything else
performance 5 and mx5parts dont seem to have any disks in for the sport brakes grr
That’s unusual & pretty naff.
Give your local dealer a call (in the next 9 minutes) and see how much they want for them, if they are in stock - it might not be much (if any) more than MX5parts, might even be cheaper, you never know…