Current UK Investment Properties

I have three UK investment properties all breaking even (rent = interest & costs).  I emigrated to Australia last year and with the current tax year end approaching I have realised there is a potential to reduce my tax bill by using the 'negative gearing model'.

In the UK there is no deduction for tax purposes of the 'depreciation' element (instead a 10% of rent is an allowed deduction for wear and tear).  I have a number of questions I was hoping to get help with:

1) Can I get the 2.5% capital reduction on my properties in the UK?
2) If so - at what valuation? Do I go back to original costs or are the market values at the point I became an Australian resident the correct valuations? (I got all three properties valued before we emigrated)
3) As the equity increased I borrowed against this to emigrate and invest in Australian property, therefore the original property purchase cost is lower than the current mortgage - do I have to make an allowance for thin capitalisation?
4) Do I have to make a withholding tax payment of 10% of the interest payable in the UK? (and if so do I get this interest back when I do my tax return?)
5) When calculating the exchange rate - do I use the average across the year or the exchange rate in effect for each transaction.

Many thanks