Offshore Income Gain puzzle

[DavidTreitel]

It has become increasingly common to meet clients who have sold non-UK mutual funds, ETFs and other non-UK investments where the gain needs to reported as an “offshore income gain”.
I was recently at one of those conferences where brilliant tax lawyers were explaining complicated bits of UK tax law; and I am sure I heard an eminent authority say that the CGT share matching rules (Taxation of Chargeable Gains Act (TCGA) 1992, s104) do not apply to offshore income gains.

Is this correct? If so, what are the share matching rules for disposals that give rise to an offshore income gain?

[maths]

The argument is that for individuals, investments in offshore funds fall outside pooling under TCGA 1992 s104(3) as they are "relevant securities" (TCGA 1992 s108).

However, company investors (ie for corporation tax purposes) the investments are relevant securities and are subject the s108 identification rules.

[maths]

If so, what are the share matching rules for disposals that give rise to an offshore income gain?

Sorry, missed this bit.

Probably TCGA 1992 s106A.