Jonathan performs around the world with well known vocal ensemble Pot-Pourri and can be seen and heard on their website (http://www.pot-pourri.com.au/bios/single/jonathan_morton/).
Jonathan sounds best accompanied by a proficient organist or pianist but is happy to bring backing tracks if you prefer. He can perform without amplification in good acoustics for up to about 100 people; old churches tend to be perfect as do rooms with lots of wood and glass.
For carpeted venues and outdoors, amplification is required and for it there will be an extra charge.