There aren't. There was a similar Great Run Local event, but there were about 10 across the country and in any event they don't exist anymore.
All parkrun needs to do is say that you run/walk/jog in your sex category - or it could have open and female.
Despite what people like to say on here, you can tell transwomen from women in nearly all situations. And someone who broke a course record would stand out, so people would look at them. No it's not that easy to police generally, so I might come fifth in my age group when I should have come fourth. But for course records, the organisers would know and could report to parkrun HQ to deal with.
parkrun should comply with UKA rules on this as the results go onto the Power of 10 website (the official record of athletics results)
I tried contacting them about this months ago and have never had a response. It is another of those organisations who don't make it easy to contact them about anything.