Kpa1 - new to this one but £15 should come back soon and any rally will see £16 £17 + in the next 6 months. May day trade of average down. Risky yes, but what is not.
I have over 34570 shares at a negative average cost in an ISA, ie recouped investment in full a long while ago and just add and trim to the core position on the moves. HTH.