"Christmas Trees." I suspect we were still using them as "Angle of Approach Indicators (AAIs') with a goose-neck flarepath; when plodding round the night-flying circuit in Piston Provosts at grass airfields such as Spitalgate. Although this was the mid 50s'! They seemed to work very well and kept you out of harms way in the "greens". Whether Oakington used them on the night in question is a matter for conjecture, or more research?