Sorry it has taken me a few days to get back to you! Your GP can write a referral letter, but often Mr PBS can make the appointment based on your email/call. Bear in mind that for Insurance and CBD you will need to follow their procedure.
PBS and Chris Mann both have experience in dealing with the VHI and Laya here in Ireland, they have given detailed reports to the insurance companies so that women can get approval. Often, the report will state that the complexity of the surgery required – requires a dedicated surgeon with a lot of experience.
The VHI often refuse the initial application and approve on appeal. I will add in a link to a paper that is often submitted to the VHI as evidence. I would also recommend using the recent media coverage of severe waiting times even for private patients as a strong factor in travelling.
You can usually send your records on ahead of time, PBS often does a detailed Ultrasound in London to help him plan his surgery. Some women here have been over to the UK on both Insurance and CBD and hopefully will be able to help. If you check the other threads you will see some of the comments.