Second home becomes main home - CGT on sale?

[someone]

I think the significance of the Morgan decision is that the taxpayer had a (signficant) change of circumstance that triggered his change so that the home was no longer his main home.

I would expect similar where, for example, someone bought a house and then was forced to move due to a redundancy or relocation deal by their employer (that they didn't know about prior to purchase)

In the longer term, I wouldn't be surprised if the last 18 months relief is only available where you're replacing a main residence. Any bets?