Say, Roman soldier up in old tree (8)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

An envelope (‘in’) of IG, a reversal (‘up’ in a down light) of GI (US ‘soldier’) in O (‘old’) plus LARCH (‘tree’). The definition is a reference to the Russian oligarch, Roman Abramovich (one-time owner of Chelsea F.C.).