Hagon usually recommend and supply the 34045 medium damped shocks for the Bonneville, which measure 340mm long - for anyone weighing between 75-100 kilos.
The standard shock length for the cast wheel 09/10 Bonnevilles (including the SE) is 330mm long. However ordering a 330mm long shock from Hagon will result in a "custom" build surcharge as a '33045' is not an off the shelf item at this time.
I have just fitted a 34045 SA1 (Black Wideline Classic 1) which has the stainless top shroud, chrome spring and black body at a cost of 155.50 delivered - I spoke to them last Friday afternoon, arrived Monday lunchtime.
Because of the angle the shock sits at the wheel itself is not actually extended by all of the additional 10mm and apart from making it slightly easier to put the bike on the centre the extra length is almost undetectable from stock. The tyre still clears the ground and seat height once on the bike is almost the same as some of the extra length is lost because of the softer than stock spring.