Hello Richard,
My measurements are:
Forestay at stemhead horizontally aft to forward face of mast, J = 2.7m;
Jib pole extends 840mm forward of forestay attachment when rigged as bowsprit;
So, mast base to end of bowsprit = 2.70 + 0.84 = 3.54m.
Your boat is much newer than mine, though, so there might be differences and it's probably best not to base any expensive decisions on my dimensions!
Best wishes,
Anthony
Anthony Russell
235/02 Sea Wyche