thanks Donna (& Elizabeth) - also thanks to Wendy in Manx Museum for allowing me access to Registers as initially I tried the 1911 Rolls office transcript (usually very good) but the Museum copy of the microfilm is very defective (the photocopies were actually unreadable !) for these years - apparently a new batch of Mormon films is on order and should replace the badly worn copies soon. Thanks also to Brian's index as I used his index to create a date index for my demographic research (still ongoing - no doubt for the next decade !) and looking at the graph I should have investigated the glitch earlier (see http://www.isle-of-man.com/manxnotebook/history/demog/bn.htm)
A quick check doesnt immediately show any other missing pages for Braddan until the 1840's when a complete book was missed (apparently they ran two books in parallel - possibly somehow connected with Braddan New Yard which took over from old yard at this time) - the IoMFHS have this on the list of things to do. However now I have the database I will try to run a consistency check to see if any other parishes have similar missed pages.