F6 Corporation Chargeable Gain

Can somebody please answer this question for me, under corporate chargeable gain,
Is this right to add the cost of an asset and the incidental (Legal fee In connection with purchase) cost of purchase in other to get the indexation allowance which will be used to reduce the chargeable gain? As followed:

Say XYZ, Disposal proceed 450,000
Incidental cost of disposal 6,300

443,700
Cost 200,000
Incidental cost of acquisition: 3,000
203,000

Enhancement cost 40,000 243,000

200,700

Less Indexation

Cost: 203,000 * 0.736 149,408
Enhancement 40,000 * 0.673 26,920
176,328

24,372

Thanks