Not sure on something?
Rollover relief is only available on the disposal of assets that are used for the purpose of a trade. Although profits of a rental business are calculated in the same way as a trade the letting of property is generally considered not to be a trade.
It is possible to claim rollover relief on properties used for the commercial letting of furnished holiday accommodation as this is considered to be a trade.
Whether a trade is being carried on is a question of fact and is to be decided on a case by case basis. Case law dictates that this is very difficult to establish.