it didn't go so well as she invited her friend along half way through,
How rude of her.
However at this point I am the one initiating contact all the time and she sometimes takes ages to reply to messages so I was only texting her to arrange dates as my efforts to start conversations over text about day to day things didn't seem to be working.
Maybe she's just plain lazy. Or maybe she's sexist, and expects men to do all the work.
She told me that she hasn't had a boyfriend for ages, which I found surprising as she is really attractive.
Gee, I wonder why? She sounds rude, lazy, maybe sexist. Some women rely totally on their looks to get a date, but don't bother to work on their personality. So they can get a date, but can't keep a boyfriend.
Anyway, I don't think you did anything wrong here. I think you two are not compatible.
I have a long time interest in psychology, specializing in relationship dynamics for 30 years.
(Please note, we give the best advice we can based on the information given in a post. For better advice, please include the age of all romantic partners.)