Seen being referenced by eadt.co.uk
Grapeshot is an analytics/tracking/"customer engagement" system. They have a page at www.grapeshot.co.uk but the bare domain generates a warning from Ublock origin.
Their synopsis for themselves is
Grapeshot uses Advanced Keyword Technology to segment inventory and improve targeting, making advertising welcome.
Worth noting, they've been bought by Oracle at some point too, so are likely to become extremely consumer hostile if they are not already.
They use a subdomain per customer, so various upstream lists contain various subdomains, but some are always going to be missed.
Given the only non-tracking usage of the domain seems to be their WWW selling their wares, seems like should just block the zone entirely