Siniat do not manufacture a skim plaster.

However, as per the GDPA (Gypsum Product Development Associations) compatibility statement, you can use any of the 3 UK manufactures (Siniat, British Gypsum or Knauf) finishing products i.e. Plasters on the 3 named manufacturers boards. The relevant finishing manufactures advice and guidelines should be followed when installing these products. Please note that certain specialist products from each of the manufactures may have varying finishing requirements so this should be checked with the relevant board manufacture as required.

Generic guidance can  be found in Annex A2 of the Siniat Drywall Manual: