Impairment loss-calculation & allocation

Can someone please help and walk me through the calculation of impairment losses and the allocation of it?

Macmillan Co incurred losses during the year ended 30 June 20X8 and an impairment review was performed. The recoverable amount of Macmillan Co’s assets was estimated to be $100 million. Included in this assessment was the factory site owned by Macmillan Co which had been damaged in a storm and impaired to the extent of S4 million. The carrying amount of the net assets of Macmillan Co at 30 June 20X8 (including fair value adjustments on acquisition but excluding goodwill) are as follows

Factory site 60M$
Other plant and machinery 15M$
Intangibles other than goodwill 9M$
Current assets (recoverable amount) 22M$
Total 106M$

None of the assets of Macmillan Co including goodwill have been impaired previously
Macmillan Co does not have a policy of revaluing its assets

Here is the part that relates to the factory site mentioned above:

Cameron Co acquired 80% of the five million equity shares ($1 each) of Macmillan Co on 1 July 20X4 for cash of $90 million. The fair value of the non-controlling interest (NCI) at acquisition was $22 million. The fair value of the identifiable net assets at acquisition was $65 million, excluding the following asset. Macmillan Co purchased a faciory site several years prior to the date of acquisition. Land and property prices in the area had increased significantly in the years immediately prior to 1 July 20X4 Nearby sites had been acquired and converted into residential use. It is felt that, should the Macmillan Co site also be converted into residential use, the factory site would have a market value of $24 million, $1 million of costs are estimated to be required to demolish the factory and to obtain planning permission for the conversion. Macmillan Co was not intending to convert the site at the acquisition date and had not sought planning permission at that date. The depreciated replacement cost of the factory at 1
July 20X4 has been correctly calculated as $17.4 million.