Wow thanks for the detailed response, some great info there, much appreciated.
Think I might go down the scuba tank route for refills. Contacted a dive shop near me earlier today, he said they have some 12 litre 232 bar tanks available for £100. Only issue being that there used, he did say they have been recently hydro tested. Should I be concerned buying a used tank? Also roughly how many top up fills would I get from a 12 litre 232 bar tank, filling 48ci tanks to roughly 2500-2800 psi?
Thanks