Perlite in 100 litre bag (75cm by 50 cm) I was going to use it to half fill my planters. Quite heavy - you will need transport, a trolley or to be strong.
https://www.amazon.co.uk/gp/product/B097F1B2QY/ref=ppx_yo_dt_b_search_asin_...
Large bag of perlite (Anerley SE20)
This offer has been gifted to someone and is no longer available.