There are some magazines that you can trust and some that you should only read for their entertainment value. The best one I know of is the Radiata. It's hard to find subscription info and I've let my subscription lapse.
You can also join one of the better conservation groups. TSA has a very nice magazine and the Behler Chelonian Center also has a wonderful magazine.
The only one I know of in the UK was called Practical Reptile Keeping. A friend bought me a copy from WH Smiths in 2013.
It was not very good with only a little about tortoises, with some nice photos but I only had 1 issue, so who knows.
The others are right though.
There is much more information here than anywhere else.