ILR to NTL Super Priority

[raysun]

Hello Peeps, I am new here and looking for answers regarding a ILR to NTL (BRP). I am an Australian citizen and have had a ILR for over 18 years. I live here with my husband and children. I am travelling to Australia urgently due a parents ill health however recently my passport was updated as it was due to expire and my surname needed updating due to my marriage/change of name. I have now applied for a NTL (BRP) using the newly released service with Super Priority at a cost of £858!!
When booking my appointment with UKVCAS I had no idea I would then be stung with another £260 as the only appointment available is in London. Surely the super priority fee would include the cost of the necessary appointment? This was not advised before I committed to the Super Priority Service and paid for the application online, so from a consumer perspective seems very misleading.
My question relates to the processing times of this application as a 'Super Priority'. I can not find details on what super priority means and what I can expect for my £858 plus £260 for an appointment?
All my supporting documents are ready to go and have been uploaded my appointment is for next Wednesday. Any advise on processing times once the appointment has taken place or things to check before I go would be greatly appreciated. Any mistakes now would be very expensive ones both in financially and emotionally as my parent awaits my urgent visit.