Trev I too would try the Sleaford route mate the road to bourne is mint and quite quick, and I understand from Bourne to Peterboghorror is quite a quick road.

Or at the very least you could cut a big section out by Going down Via Ancaster and then taking the back road to Grantham that goes past Barkstone Heath, and then at the roundabout near the Army camp you follow the road to the A1. I used to be able to make Lincoln to Grantham in about 30 mins going that way.