Leaky capacitors need replacement?

From what I can decipher from Roger's schematic (which has a series of iterative changes written in pencil on it), BOM, and notes it is an electrolytic power supply filter capacitor, 33 uF/350V. As I said previously, the OP should replace it with the same value.

It’s a Music Reference RM-10 and he should use the exact value for the replacement. I can't remember the brand that Roger used, we may still have some lying around, but the Nichicon’s pointed out by George are a good choice and should fit inside. They were one of Roger’s favorite capacitors. As for getting someone to put them in any competent local tech can do it.  

Which MkII do you have, the fixed bias version (you set the bias) or the cathode bias version (amp sets the bias)? I ask because all fixed bias MkIIs are well over 3 years old (mine is at least 15) to my knowledge. A cathode bias version may be within that time window.