Question Author
Thanks ljdksa but I fear crowd or group is not the answer. I should perhpas have explained the intersections:
For 6d - gunge (5) I have ?l??? - the 4th letter being the last of the word for 11a - cluster (5) where I have s?r??.
There is a word 'sorus' which means a cluster of sporangia on the underside of a fern frond - but this would then give ?l?s? for 'gunge' and this would mean that the answer could not be 'slime' which is the nearest I can get for gunge.
All very irritating!
cwaddict