A NEW house-swap scheme for the over-55s has been launched in Britain, part of a European initiative called Senior Vacation International. Subscribers to the SVI scheme pay pounds 20 annual membership, which places their details on a central database. If an exchange is agreed, an arrangement fee of pounds 40 is charged. SVI expects to recruit members initially in all West European countries, with the US and Eastern Europe following later. Further information: SVI-UK, 55 Tilsworth Road, Beaconsfield, Bucks HP9 1TP (0494 672259).