"It felt like such a lottery to get an appointment"

I rarely contact my local surgery but had a new health issue which caused me some concern, just over a year ago. 

I am giving feedback here because I have just completed the GP Patient Survey, and it didn't enable me to explain my concern. 

I went to the surgery's website which advises to book via the NHS app.  I was advised by someone else that you have to book an appointment at exactly 07:00 hours in order to stand a chance of getting one of the very limited appointments available. 

I did this and there were several time slots available.  I selected a slot and filled in a box which asked for some details of the health concern involved.  Having completed this, I clicked through to another page and a note appeared advising that my slot was no longer available.

I went back to the start of the booking system, by which time there were only 2 slots left.  I selected one of these, completed the requested information as quickly as possible, just typing one word in the box asking for details of the health concern, and was lucky enough to get the slot. 

I saw a GP, who was excellent, and was referred to treatment by another practitioner at the surgery, who was also excellent.  Great treatment but I was left feeling uneasy that it felt like such a lottery to get an appointment in the first place.