These batteries are still available, but you need to search around, and even then you are looking at elderly stock, priced £29 to £35, postage extra.
Your simplest and cheapest solution is to purchase a new cordless drill from your local d.i.y. superstore. They have come right down in price, and the new generation lithium batteries are now available.
Not generally known is the fact that ordinary d.i.y. (non-professional) drills are designed to have a 20 hour life. So don't source a battery for a dead drill.
mcphil, September 2009