Transfer of investment property to owner occupied accounting method

Hi.
Im confused on how to deal with an accounting issue. It is as follows…

Future Plc Ltd measures its land and buildings (property) at re-valued amounts. The following is a list of balances on the property, plant and equipment (excluding investment property) accounts as at 1 January 2015 (£000):

Property Plant Fixtures Vehicles Total
4,010 1,560 1,170 300 7,040

Accumulated Depreciation as at 1 January 2015 (£000)
Property Plant Fixtures Vehicles Total
401 702 351 108 1562

Depreciation is charged at the following rates:
Property 2.5% per annum straight line
Plant 15% per annum straight line
Fixtures and fittings 15% per annum straight line

A full year’s depreciation is charged in the year of acquisition and none in the year of disposal. Depreciation is charged on the closing cost/revalued amount each year. The 2015 charge for depreciation has not yet been included in the financial statements.

There are some disagreements within the Finance Department on how the following events which occurred during the year should be dealt with in the financial statements of Future Plc:

Future Plc acquired an investment property at Bloomfield back in January 2011 which has been leased to a third party from that date. In order to accommodate the group’s growing workforce, additional workspace was required and the property at Bloomfield will provide this additional space.
On 1 March 2015, a decision was made by the board of directors to change the use of this property. The existing tenants were given one month’s notice at the beginning of March 2015. They vacated the premises on 1 April 2015.
The property was renovated and the finance department staff eventually moved in on 1 July 2015. The re-classification of this property in the financial statements from investment to owner occupied was not made during the financial year.
The property is currently included in the draft financial statements as an investment property, at its fair value, on 1 January 2015 of £3 million pound. It has been established that the property was worth £2.9million on 1 March 2015, £2.8 million on 1 April 2015, and £2.4 million on 1 July 2015. The property at Bloomfield has 40 years’ remaining useful life. The financial controller is confident that the above transaction should be dealt with under IAS 40 Investment Property, whilst some of the other staff believes that the transaction should be dealt with under IAS 16, Property, Plant and Equipment.

How do you account for the transfer? What is the appropriate solution for this. Many thanks, Shannon.