Because they cannot buy in the volume that Amazon does. If you buy through a charity for a disabled person you can also claim the vat back

Stan, can’t you get disability aids from Social Services or the NHS, I remember when my mum was alive we received lots of gadgets from them, they were all in loan and had to be returned when the user died.

I have to say they provided some really good items, as my mum’s mobility deteriorated they constantly changed tings to cope, one-off the things they provided were beds, the last bed we have before mum’s death was fantastic, it went up and down, at night it was lowered to floor level, a mattress was provided to be placed next to the bed so that in the event if mum rolled over she went straight into another mattress, also the actual mattress was hooked up to the electricity so that it ‘moved’ which meant mum never got bed sores. It might be beneficial to contact your Social Services and have a word with them.