What is a monument and what is a museum- VAT definition for HMRC

We are a Board of Trustees who are trying to decide on VAT.

Our project  aims to restore the Marquess of Anglesey's Column which has been closed to the public for H&S reasons. It was originally defined as  ‘The advancement of the education of the public by making accessible to the public, and the preservation, maintenance, upkeep and repair of, the Napoleonic War Memorial, known as the Marquess of Anglesey’s Column on the Isle of Anglesey’ ( extract from Charity Commission Register). 

The crunch seems to be whether HMRC would regard us a museum or a tourist attraction. The Column is empty apart form the internal stairway and is listed Grade 2*. We also aim to restore a Grade 2 listed cottage next to the Column to sell tickets, provide toilets and sell light refreshments.

Advice would be welcomed.