One of the highlights of the EFG London Jazz Festival programme at The Vortex was a late night performance by Double Trouble, a quartet led by the Berlin based saxophonist and composer Peter Ehwald. Ehwald is probably best known to UK jazz audiences as a member of the Anglo-German group Paragon featuring Ehwald’s compatriot Matthias Nowak on double bass plus the British contingent of pianist Arthur Lea and drummer Jon Scott. Both of Paragon’s albums “Quarterlife Crisis” (2010) and “Cerca” (2014)…