Thanks for the comments
When looking at this turnout, it looks like the gap between the inner rail and frog is wide enough not to create a short circuit when the wheels cross over it.
However, as WIMorrison said there is a caveat that a wheel may touch both, hence cutting the inner rails at the yellow circle is more of any insurance to prevent a short circuit .
Also a DCB said cutting the rails may weaken them, other good point to consider.
I could test my locos and wagons with the biggest wheel diameter to see if a single wheel will bridge the gap to create a short, then that will dictate whether to cut the rails or not, or cut my losses and buy new turnouts.
Upon further searching I found this on the "wiringdordcc" web site I found this, where he also cuts the rails.
May be cutting the rails as close and as fine as possible (not using a dremel) is a solution.
Thanks