Secondary tax on companies : paid during 1993/1994 to years - section 64B subsequently amended with retrospective effect to provide an exemption - taxpayer entitled to refund of tax paid - whether also entitled to interest - Sage Life Limited v Minister of Finance and SARS, judgment of the High Court, Transvaal Provincial Division, delivered by Basson J, on 10 October 2001 (Case 24379/00)