Do I have to pay the congestion charge for Brighton to St Georges Hospital, Tooting?

The congestion charge covers an area of somethiong like less than 5% of London so you are extremely unlikely to go into the zone unless you travel right in to the centre of London - if you cut across from the A23 in the Norbury/Streatham kind of area you are still at least five miles away from the Southern edge of the zone. Its all very clearly signposted