CG55001 - Conversion of securities: instructions on share reorganisations
The instructions on reorganisations are at CG51700+
CG51730 defines original shares (securities)
CG51730 defines new holding
CG51820 deals with consideration paid at the time of the conversion
CG51875+ deals with consideration received at the time of the conversion
CG51890 describes the apportionment of cost.