Capital gain on disposal of plant after claiming cap alls

I'm hoping I have this right but it comes up so rarely I'd welcome a second opinion.

My client has disposed of 2 substantial items of plant and machinery, one at a price well in excess of cost.  Capital allowances were claimed. My understanding of the treatment of this is that:

Proceeds will be treated as reducing the general pool, but restricted to the original cost of the asset.

The excess over cost will be treated as a chargeable gain.  The asset will not be a wasting asset as capital allowances will be claimed.  Indexation allowance will be available.

I'd be grateful for any thoughts.