The government and authorities are very aware of this 'wasting assets' and 'disposing of assets' and could force you to pay for mum's care no matter how many years after the transaction.
Disposing of assets
If you have given away or transferred a capital asset (property, savings and so on) in order to reduce your charge for residential care, we can treat you as still having the asset and charge you accordingly. We look at each case individually, and there is no time limit on disposing of assets.
http://tinyurl.com/3oad5p
Quite right too. Why should I pay for your mother's care to make you richer?