Is the company in administration, or have they wound everything up?
Are the email servers still accessible? (Is the email still working?)
Where are you DNS records hosted?
Well I've checked, DNS is still up and functional. Looks like the DNS servers are with
domaincontrol.com which looks to be a registrar called Wild West Domains.
I can see mail is received by
mail.bikepacker.co.uk and that resolves. The IP address it resolves too is owned by Heart Internet.
A quick port scan of
mail.bikepacker.co.uk shows that usual mail related TCP ports are open (IMAP, IMAPs, SMTPs).
Can you confirm you have access to your email?
I think the steps to recover from this situation are:
1) Download all email using a client (Outlook/Thunderbird) via IMAP - that probably means moving it into a local mail folder or some such depending on the client you are using.
2) Setup new email hosting and setup appropriate DNS records. You will also have to update the SPF/DKIM (and to a lesser degree DMARC) DNS records so that receiving mail servers hopefully trust the email you send rather than treating it as spam, rejecting or silently dropping it.