The mail postal packs which we use for most of our supplements are HDPE (High-density polyethylene) plastic code 2. The lids are: PP (Polypropylene) plastic code 5. Manufacturer guidance on recycling states: 'As far as we are aware the postal packs are recyclable but this is dependent on what the applicable council takes in their recycling plants as all are different.'
Generally speaking most councils recycle plastic types 1,2,4 and 5 though this can vary from council to council. Both the main bottle (type 2) and the lid (type 5) should be recyclable by most councils. Number 2 in particular is easily recyclable back into items such as non food containers, detergent bottles, recycling containers and floor tiles. There is some useful information on plastic types here - https://www.pureplanetrecycling.co.uk/types-of-plastics/