For the record OP hasn't been back since 19:44 on 14/12/2018 so obviously isn't interested in a reply, or has solved his problem.
My experience is that 265/75R16 tyres should cause no problem (not even close to a problem) unless running excessive offset, which explains my question.
In my shop we've been working with a customer on fitting bigger wheels and tyres, with no suspension lift. You can see where the problem is, in this picture:
We've developed a fix, at least partial, by cutting out that section of the mudflap and rebuilding without the raised corner.
It is possible to go further but this involves cutting metal and since the vehicles we've been working on are new we weren't allowed to do that.