Retrieving domain access

Hello, we’re currently building a new website for one of our clients in the UK – CARAH Care – their managing director has sold the business and left but has not communicated any information regarding their current website. Our web team require domain access to support the launch of the new site and to ensure effective migration from the old to new. It looks like you might be hosting so we’re tring to find out if we can track down the domain log ins. Can you help?