I have used the ladies restrooms ever since I started to go out dressed and have never had an issue. It certainly gives an insight to a womans world. I have been in with girl friends and they sit and chatter while sitting in the stalls while there is a lot discussed outside. I understand why some have inhibitions but if you feel comfortable in yourself then go for it.
In the U.K. there is no actual law that stops trans or crossdressers using a restroom. It has always been a given that men use the mens and women use the ladies. There are laws about offending public decency and public order offences should there be an issue and not read anything to say that there has been anything that involves the crossdressing/trans community. Recently, through the furore about self identifying males, there was advisory legislation that could debar trans using the restrooms. It was only advisory not a criminal offence and unclear how it might be enforced and I have seen nothing nor experienced anything that has made any changes. I certainly haven’t.
A lot of stores now have what are called single sex toilets – they used to be called toilets, as it is less wasted retail space. Service stations and smaller outlets have had these for years and I feel that we should not be using disabled, as sometimes advised, as if you aren’t why should you have to? Again I do understand it would be a reason if you are unsure of yourself or directed by a member of staff as not cause any issues.