You need to go to Smartseal they have all the products you want. It’s dead easy to do. If you are restaining you must use the tinting powder only with the Matt finish, you can then overcoat with Satin or Gloss. I do mine every two years
smartseal.co.uk
Great company to deal with
PS when mixing your tint use a 5ltr thinners type tin, measure with a spoon each time you mix, then keep shaking to keep the tint mixed as you use it, obviously from a roller tray