Map 2 - XXX Marks The Spot! - map 1
From Northampton:

Come in on the A45, pass Rushden, Higham Ferres and Stanwick roundabouts. At the next roundabout you should see a MacDonalds/BP sstation, turn right towards Raunds, keep going until you come to a second roundabout, got straight across till you come to a third roundabout (mini), go straight across towards Chelveston, in Chelveston you'll come to a T junction opposite the Star & Garter pub, take a right, go up the hill and take a left turn at the top towards Caldecott, the village hall is immediately on your right.

From P'Boro:

After crossing the A14 at Thrapston, drive for 4 miles (ish) until you come to a roundabout, take the left turn by MacDonalds/BP sstation towards Raunds, keep going until you come to a second roundabout, got straight across till you come to a third roundabout (mini), go straight across towards Chelveston, in Chelveston you'll come to a T junction opposite the Star & Garter pub, take a right, go up the hill and take a left turn at the top towards Caldecott, the village hall is immediately on your right.