Thanks to Sting and musashi5150, the trackloader, including the bootblock header stuff, is now 486 bytes.
Also attached is the shorter decrunch version too which is now 838 bytes.
Thanks guys, your advice has been really appreciated.
EDIT: Found some more savings - trackloaders are now smaller still as per new byte values.
EDIT 2: Found some more savings - trackloaders smaller again, as per new byte values.
EDIT 3: Added a version that does some nice old skool $dff180 colours on decrunch - adds 10 bytes to the code, but come on - it's for decrunch colours! \o/
EDIT 4: Found yet another saving - new byte sizes as per above.
Source code removed - newer smaller version posted further down this thread...