Luis is ready for decannulation - help!

Luis has had his trachy since he was a month old. He had heart surgery which left his vocal cords paralysed and had a grade 3 stenosis due to repeated intubation. We didn't know if his vocal cords we're permanently damaged or just bruised but over his 2 years with his trachy things looked like they were moving, albeit slowly, in the right direction so we've just got on with life with the hope that one distant day he would be trachy-free.
He went in for a LBT on Thursday, just a general review so we didn't get our hopes up but we were flabbergasted when his ENT surgeon announced he could be decannulated, not least when they said they'd start the process straight away. OMG!!!
First stage was to downsize his tube which he coped with fine but we have really hit a wall with the next stage which is sleeking over the tube. On the one hand Luis has only really ever known breathing via the trachy so the sensation of using his upper airway is completely alien to him, but on the other hand he is 2 and terrible - he really doesn't like being messed with and will fight against the silliest of things like having his nappy changed and he is absolutely refusing to let anyone tape over his tube.
It is so frustrating. We can occlude at night, when he is completely zonked out and he is fine, sats 100%, all going brilliantly. But the minute he wakes and realises that the sensation is different he pulls off the tape and we then can't re-tape while he's awake.
We've been at this for 3 days now, and the hospital are starting to talk about sending us home and the trial not working and I'm just desperate as I know he can do it. Medically everything is okay, it's a psychological, behavioural thing more than anything else, I think. I know he has to re-learn how to breathe but we also need to get round his stubborn 2yr old mind.
We've been playing around with his swedish noses during the day, covering them with clear tape to increase the resistance and that goes well as he can't see the tape so doesn't think there is anything different about them, but he is still relying on the leak around the tube rather that using his upper airway.
Does anyone have any experience with this or any advice they could offer, we really are struggling. This is something we thought would happen one day but not in the near future, so we hadn't in any way prepared ourselves or looked into the process and how best to prepare Luis.
This is an amazing situation to find ourselves in and I just really want to make it work - I can't even imagine the impact it would have on our lives to be trachy free, I guess you all know what I mean.
Love Helen (& Luis x)
PS - Sorry for the very rambling blog, it's been a long few days...