Stud walls are not the best to fit brackets to support TV's of that weight, i'd recommend if you was going to fix the TV, you try find studs in wall first then measure distance between them, then find brackets that will fit across them. You can buy stud detectors from good DIY stores for less than a Tenner. Be careful of the cheaper ones though as they can give false readings and you can end up with a lot of holes you dont need. Follow this link to a decent detector.
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