@Milky I used something like this https://www.ebay.co.uk/itm/Nylon-Ba...08?hash=item3d3f291ebc:g:ehQAAOSwOyJX7m4dlots Lots of sizes available.
I used two of these: https://www.webcon.co.uk/products/9978-air-filter-breather-adaptor-12-inch/ One for the crankcase breather and the other for the tank vent connected with the original VW reducer. https://www.heritagepartscentre.com/eu/055129638-air-vacuum-pipe-adaptor-reducer.html If you have alloy filter covers and tap a hole for the elbows there is no need for a lock nut; they can’t unscrew.
If you have the very common tallish ICT cone filters (that are glued together) try to not let the larger crankcase vent pipe put strain onto it, they have a tendency to fall to pieces.
Theres also the annoying people with UK seller but ship from China via the EU so you get a long delivery tine and a Brexit Customs Violation sticker... Go for the one with guaranteed delivery this week , even if the price is higher.
