Even if the UK has a zero-tariff trade agreement with the EU, companies will need to prove that their product is of UK origin to benefit from this (usually, this means that 50-55% of the product has to be locally sourced). The exact terms of these rules between the UK and the EU are yet to be negotiated.
Your business should consider
If you are a supplier, has your customer asked you to provide proof of where you source your content? Would you be able to provide it if asked?
If you buy your components from local suppliers, have you thought about conducting an audit of where they source their materials?
Resources and information
UK Government technical notices on EU FTAs if there’s no Brexit withdrawal agreement: http://www.gov.uk/government/publications/existing-free-trade-agreements-if-theres-no-brexit-deal