Re: warranty on spare parts
Consumable: Parts subject to potential excessive wear and tear ( belts, brushes, light bulbs, filters, seals and such like). There is no “law” as such only what can be regarded as a reasonable working practice. 90 days to 12 months a reasonable period as far as Trading Standards would expect from traders.
You can set your own guarantee period if you wish provided you make it clear (in writing) so your customers are fully aware toward what they are paying for ( your trading terms & conditions).