You have applied for a UKStandard Visitor Visa and the processing time is taking longer than usual. You want to expedite the application because your travel plans may be disrupted. The first step is to use the wizard at Visa Processing Times to see if your application falls within the expected times.
If you read the government website it has all the fees for different criteria visa I’m afraid you will have to pay £800 for the priority service
Many thanks, I was just double checking as I called the goverment helpline and the information given didn't sound correct,