This forum has been really useful to me in the past, so I am sharing my recent experience of application for naturalisation and use of UKVCAS with all.
I completed and submitted my application in the first week of January 2019. Before I submitted my application, I was trying to find out what dates are available from UKVCAS but there is no such option available. You have to complete the online form, make the payment and then only the option for selecting the centre and dates becomes available.
Anyway, I completed the form, paid the fees and then selected Birmingham and 10th Jan as my appointment date. Once I had made the selections, then I was able to register and login to the UKVCAS site.
The site then provided option for uploading the documents which was rather straightforward.
I was provided a document checklist on completion of form, so I used that to submit the relevant documents.
Finally, I had to print off the appointment confirmation QR code and take along to the appointment.
My appointment was scheduled for 1300 hours, so I reached there half an hour in advance. But the UKVCAS team was running late so I was told to go away and come back exactly at 1300. When I went back, I had to wait till 1325 before being given a token number to sit in the waiting area.
After a long wait, I was called in for a biometric, but the machine did not function properly and I was advised that the person checking my documents will take the picture and submit the biometrics as well. (I was like, so why dont they do this as a matter of course?)
Anyway, the lady who was supposed to check my documents just scanned my passports, completed the biometrics, but did not check my documents.
The appointment was completed in 10 minutes.
Overall, it wasn't a bad experience except it felt like a waste of time going all the way when they did not bother to see the original documents. Biometrics used to be done at Post Office as well previously, so why could that not have been continued. On the positive side, it was a free appointment, I was able to upload all the documents in advance and I did not have to submit my original passport as I will be travelling shortly.