"Appointment constantly rearranged"

I've been under the same neurologist for 10 years. Last year I suffered a major seizure which ended up with three separate hospital visits due to constant seizures and vomiting and in the end a 3 week hospital stay at Princess Royal hospital (I was told by Lewisham I had a brain contusion and then just sent home). I had a routine appointment due in December 2017 but that was canceled due to my hospitalisation and I required an earlier appointment. I was seen in August 2017 after my discharge from hospital and was then sent a new appointment for a follow up in December 2017. Due to being on holiday around christmas I rung up and changed my appointment to January (giving over a month's notice). Since then I have had letters every few months changing my appointment 'due to unforseen circumstances'. January 2018 got moved to April 2018 then to October 2018, a full 14 months after my last appointment and 11months later than the recommended 3 month check up after changing my medication. At this point I went into the hospital to talk to pals. The staff were amazing and sorted out an earlier appointment in September 2018. Although this was still a lot later than needed at least it was earlier than October 2018. I have recently received a new letter stating again 'due to unforeseen circumstances' my appointment is now in January 2019. I am now giving up hope on being able to see my neurologist at all. This is completely unacceptable and is causing yet more undue stress. I understand that the department can be overwhelmed at times but I just hoped that I could be seen at an arranged appointment