Its been pretty hot in england over the last few days and my tank temp has risen from around

75.2 Fahrenheit - 24 Celsius (if i can remember rightly)
to
86 Fahrenheit - 30 Celsius

What should the max temp be for goldies?
Am i over heating them?

WOW thats hot Hun.

Thats why to hot for them. I would be turning off the heater. Then cracking the tank lid if you can and get a fan that will blow some air across the tank water. Then if that doesn't help then maybe some frozen pop bottles. you know like 2 Liter soda bottles (plastic), fill with water then let freeze (I would have two of them so you can rotate them), then let them sit in the tank. You could also place some rocks in the bottle so it would sink....Either way this should help keep the temp down.

Goldfish in normal temps should only reach about the 82 mark

Owww koko, thanks so much for you help! ill be doing that 2day!

No problem hun, always here to help

Hm, I wonder, do you have air condition Tanya, or is that an american thing?.....I remember a french friend telling me years ago, when they had snow on the cote Azur for the first time in ages, and nobody knew where to find heaters or how to make them work!
Whatever you are doing, I would crank up the airsupply a lot, water has less oxygen when its warm like that.....
Good luck with your fish!

You dont find many air conditioned houses in england because the weather most of the time is extremly dull I have got it to go to the 82 mark because ive had the fan in my bedroom. I do have a big bubble stone in both my tanks aswel

Since I live in a tropical clime, Im planning to get rid of the lid altogether and put a sort of plastic mesh on top.

Would letting ice drip from this mesh work?