(19)

(11)

EP 0 920 602 A1

(12)

(43) Date of publication: 09.06.1999 Bulletin 1999/23 (21) Application number: 97937674.0 (22) Date of filing: 20.08.1997

(51) International Patent Classification (IPC):  G01C 21/ 22( . ) G09B 29/ 10( . ) (86) International application number: PCT/GB1997/002227 (87) International publication number: WO 1998/008056 (26.02.1998 Gazette 1998/08)

(84) Designated Contracting States: AT BE CH DE DK ES FI FR GR IE IT LI LU MC NL PT SE (30) Priority: 20.08.1996 GB 19960017483 (71) Applicant: Turner, John Richard Miles Norwich, Norfolk NR1 4BG (GB)	(72) Inventor: Turner, John Richard Miles Norwich, Norfolk NR1 4BG (GB) (74) Representative: Whitaker, Iain Mark, et al  Sommerville & Rushton Business Link Building 45 Grosvenor Road St. Albans, Hertfordshire AL1 3AW St. Albans, Hertfordshire AL1 3AW (GB)