If you own property overseas, you usually need to make a separate will in that country, taking into account local succession laws and inheritance tax. For example, in many European countries a proportion of your assets is automatically inherited by your nearest blood relatives (not including your spouse or civil partner). In some countries inheritance tax (or its equivalent) can be punitive unless you take steps to minimise your liability.
Your foreign will and the will you make here must dovetail with each other. You may also need tax advice across all the territories where you own property, so make sure your solicitor here is aware of your foreign assets.