Should trades be averaged under the "same day" capital gains tax rule?

Say you have the following list of trades:

• Buy 100 XYZ at £50 a share on March 1st
• Buy 100 XYZ at £51 a share on March 1st
• Sell 200 XYZ at £60 a share on March 20th

This would result in a net profit of £1,900, disregarding of whether you average the first two trades or not.

Now, according to the official guides:

All shares of the same class in the same company disposed of by the same person on the same day and in the same capacity are also treated as though they were disposed of by a single transaction, TCGA92/S105 (1)(a).

It seems to me that I should not report the first two trades as two distinct trades at all, should I? They should be replaced with:

• Buy 200 XYZ at £50.50

I know that in this particular scenario the net gain would be the same, as there are no disposals of the same asset on the same day, but it’d be good to know the correct approach.