The contract will say what is included in the sale and what is not, see fixtures and fittings. Yet despite this, vendors sometimes remove items such as curtains or light fittings.
If fittings and fixtures are included, this means those that the purchaser saw when first inspecting the property. It is not possible for the vendor to replace an item (for example, the curtains) unless the purchaser agrees. It is much safer for a vendor to replace the fixtures prior to putting the house on the market, rather than removing items after the contract has been signed.
If items are removed, the purchaser can make a claim for the return of the items. Depending on the value of the items, a claim could be made in Court for the return of the items. Legal advice should be sought before proceeding.