Check the price of the GTE on your company car scheme, it was £700 a month on a 2 year lease when I ordered my GTD, now it's reduced to £360 with both lease providers... would have saved me another £100 a month as the tax is only £55ish!
(that's £360 by salary sacrifice)
Just had a look on one of the two providers we can choose from and the GTE is about £365 on there, would work out about £275 a month all in after the tax saving on salary sacrifice then adding on the BIK.