On offshore property

My clients are a group of individuals involved in property development owning and management. They mainly own commercial properties that they have either purchased or developed (e.g. shopping centres warehouses offices etc.) and have then retained the ownership of them letting them out to commercial tenants. The properties are generally owned via limited companies.
They have recently purchased several properties some in the UK some in Europe and some in the middle-east but I have been advised that they are all held via a company in the British Virgin Islands. It has been suggested to me that I should complete a non-resident landlord's form in respect of the rent being paid by the UK tenants to this company to avoid withholding tax having to be deducted.
I should be most grateful if readers could provide any general advice or information on...