CG52594 - Share exchange: section 135 TCGA 1992: 1982 holding
If the original shares were held in a 1982 holding, see CG50870+, the new shares or debentures will also be held in a 1982 holding. For rebasing and indexation purposes the valuation you need is of the shares the taxpayer actually held on 31 March 1982. Any later takeover will not affect this valuation.
If the original shares were quoted on 31 March 1982 then their value at that date may be publicly available. Otherwise you should refer the valuation to Shares and Assets Valuation even if the later takeover is by a quoted company. The valuation you need is of all the shares held on 31 March 1982 and not merely the shares sold.