Mellotronists

I have what I think is a Mellotron Mk V (Double Console, Black stand 
up cabinet). It originally belonged to Oscar Petersen, Canadian Jazz 
keyboard player/composer, (it has 3 original racks of tapes, in 
addition to the two already in the machine, in their cases with 
delivery tags from London bearing his name attached)- but passed 
through the hands of Hugh Syme (keyboard player for Max Webster) and 
finally ended up with me.

Wondering about sources for enthusiasts groups and possible value of 
the instrument.