7A can be linked to nine unclued lights (three of two words, one of which repeats 7A) – in five cases as a prefix, in four cases as a suffix.

Across

7 Fifth of November and no old penny for the guy (3)
11 Engineer’s ancient letter stored by British Library (6)
13 Directions to compel and ensure obedience (7)
15 Field football team, missing second half (5)
17 Move between vessels to facilitate requirements of port? (6)
18 Prophet found in...