i'm not understanding the concept of trying BLW and doing purees from 6 months. you do know that the two are mutually exclusive?
dave, ach, what a pita for you. i've seen a few (like, say, 10-15 or so out of a membership of about 1500) people mentioning this on my forum. while 10 ish isn't a statistically solid gold sample, it does seem that some babies do just lose their gag reflexes later than others, which is stressful whether you're trying to feed them or let them feed themselves.
from what i recall, most of them just 'clicked' at some stage, i'm sure i remember one at nine months and most thereabouts. interestingly, i have other pages on my site with passages from old weaning manuals and it seems like 9 months was until recently a fairly common time to start weaning in any case.
i dunno what you can do, though, cos it must be just so ICK apart from anything else. re your (understandable) stresses, i always recommend doing an infant resus course before weaning (actually i think they should be mandatory for all parents) and i am reminded of the fact that when dd gagged we used to do really lunatic exaggerated chewing faces at her and say nyum nyum nyum etc. that may just have been to occupy ourselves while she did her thing, though.