Hi Alexa
Welcome to the forum. We don't have any immediate plans to update the Acari but if you send me a list of the species that you need adding then I will certainly add them to the database as ad-hoc additions in the List of Additional Names and publish the TVKs here. The new species will then be available in the next Recorder6 taxonomy update or can be added manually to your copy to get you running quickly. :)
Best wishes,
Chris R.
Chris Raper, Manager of the UK Species Inventory, Angela Marmont Centre for UK Biodiversity,
Natural History Museum, Cromwell Road, London, SW7 5BD. (tel: 020 7942 5894)
also Tachinid Recording Scheme (http://tachinidae.org.uk/)