I believe the end goal is to have at least a foundation degree by the time you reach PO? Things may have changed? HNC/HND can be done by use of learning credits. I did my HNC through Perth College (Distance Leaning), and "Safeguard" I had it cracked in 6 months, it wasn't hard the only sticky bit was popping up to Perth to spend 24 hours in Scotland to qualify as a "Scottish" student for their funding rules. There was 3 of us doing it in the Training School at Wittering with no students to worry about for a while is was pretty much full time HNC.
To answer the question you will start studying towards whatever qualification they give you the day you arrived at Sultan.