Wow thanks, that was such a quick result from 2 people with more knowledge than me! Trouble is that I must have got another answer wrong (which connect with it)! 7 letters 'To cover completely on all sides' ---E-R- (if I am correct) & the 2nd letter I think is an N
Many thanks to the 'bright sparks' who helped me solve the puzzle. It WAS Benthos & envelop which connected with allusion (I had put a wrong answer for that one, which led to my confusion).
I am amazed at the rapid response & will be using The AnswerBank more often! :)