Trading losses relief

Suppose trader has incurred trading loss of 5000 and chose “total income” relief. His total income in both current and previous year is 0. But he has chargeable gains of 10000 in current year.
He has capital losses b/f of 7000.
how the relief will be obtained?
Chargeable gains – 10000
less: trading loss – (5000)
less: cap loss b/f – (7000)
Net chargeable gain = (2000)
Can this figure be negative ?
or cap losses b/f will be restricted to 5000?
but how the cap losses b/f can even be provided… bcoz it is only allowable upto the amount at which AEA of 11300 is utilised (according to AEA concept)
:/