I didn't take it any further - it didn't feel like a risk I wanted to take with my basses.
However, their website tells me that the company has gone from three reviews, to over 17,000 reviews, in 6 months. That's equivalent to around 3,000 reviews per month or 100 per day, every day of the week.
So, for all the healthy cynicism displayed by basschatters, 4 people an hour (throughout the day and night) are happy enough with the service to leave a positive review.
Does that amount of shopping traffic sound plausible for a business that is less than two years old?
Companies House entry here.
https://find-and-update.company-information.service.gov.uk/company/15411845