Licensing authorities are responsible for issuing gaming machine permits in alcohol licensed premises and family entertainment centres. For a full explanation of the definitions, read: Gambling Commission, gaming machine permits
You will need to apply to the licensing authority where the gaming machines will be used. This is usually the local council, if you do not know who that is, see: Gov.UK, find your local council
In West Suffolk, there are two licensing authorities, Forest Heath District Council and St Edmundsbury Borough Council. To apply download the correct form and send it to the relevant licensing authority.
A full list of fees can be found in the related documents section.