HI,

Use the standard red potatoes (yellow flesh) as they don't disintegrate as much and taste really good. (What my local uses)
The leftover oil from cooking potatoes tastes really good excellent for re-use.

Nick

HI,  blimey my second post since the forum started up! ;D

Haldi is correct, the local restaurant that I have had gravy and oil samples from use the oil from roasting the Bombay potato's.  It has a nice aroma and is quite sweet tasting. 
I had a sample from their fryer used for bharji's and chips etc and it was horrible very pungent tasting.

Nick

I'm very intrested but its a difficult week for me work wise, if it could be during the Christmas break I could make it.

Nick.