Deck in MA had Smith & Allan Cedol Wood Preserver Clear applied. Seems to be working. I see zero mention on yr website. Appears to be a UK product. Have you reviewed?
"Cedol wood preserver is a high quality Cedar cladding & decking oil which penetrates deeply into timber surfaces, providing protection against extreme climate conditions and UV fading. The product dries to a clear ‘wet look’ finish, is dirt resistant and offers protection against algae and fungi. The product does not peal, flake or blister and prolongs material life by eliminating
cracking, splitting and discolouring." Applications
Cedol wood preserver is suitable for use on timbers such as Cedar; Pine and Larch amongst
others. The product may be applied by brushing, spraying or dipping and generally is a one coat
treatment, depending on the age and condition of the wood. Reapplication is recommended
every 3-4 years."