Welcome to the forums
@lodgey50
Hopefully you've contacted your local team. (Or dialled 111)
The issue here is we don't know what or how much your insulin regime is. If you have no pancreas at all you are presumably T3c and have no insulin production. (And that lack of knowledge is one reason why forum rules don't let us give specific dosing amounts).
At this point are you on a basal/bolus regime (lantus plus short acting)? Are you on one dose of lantus or splitting it?
Personally I would just inject away if my lantus was only a few hours late, but with a 6 hour gap it's going to be a pain, because if you do that you'll have 6 hours on the next evening when you have a double dose in the system. One way to deal with that would be to inject the next dose late (say at midnight) and gradually work your way back to the 8pm time, but you'd need to be very cautious about hypos.
Another way would be to manage the day by giving small doses of bolus (short acting insulin) but that would depend on your confidence in adjusting insulin doses according to your readings and I doubt you've got there yet.
Add in the fact that T3cs often have reduced hypo awareness and I urge you to be very careful and do lots of testing (hopefully you have a glucose sensor with alarms).
Really the best advice I've got is contact your team and keep testing.
Good luck and do let us know how you go.