Thanks for the input everyone. I ended up trying some Big K restaurant grade big block charcoal to try. Before I used this the Kamado still smelt of the old acrid smoke. I decided I’d try to do a cider can roast chicken as a low risk option for a first cook. I used the full charcoal bucket and some wood twizzy lighters instead of the Looftlighter I got in my starter kit, got the coals nice and lit, and left for about 30 mins before getting to roasting temperature and stable.
The end result was the tastiest roast chicken I’ve ever had or cooked, and the Kamado last lost the acrid smell too!
I can’t say whether it was the change of brand of charcoal or a more assertive load of the fire basket yet. I guess I’ll have to try the KJ coal with the technique I used with the Big K. I won’t risk it on a brisket at the weekend, but will let you all know how it goes with the KJ coal on a direct cook.