this looks overly optimistic...
They claim 1cm PPK - post processed. Or 2cm RTK.
No spec of the receiver but as they are working with uBLox in the rest of the products the description looks like a uBlox M8. Now go and look what uBlox specifies. For the receiver.
This is a solution with differential corrections - one base station and a mobile unit - the "rover" - which has to be not too far away from the base station.
Emlid specifies 10km for a moving rover.
A L1 only solution requires very stable reception
conditions. Very good sight to satellites and optimal sat distribution.
I think, you have one of their actual receivers and rovers. Over let's say 48 hours, how does the footprint look like? And if you move the rover, how stable is the track, how sensitive is it about disruptions? And dynamics in movement. GPS
outages are not that important in marine
environments (but in harbors or fjords) - but how fast does the rover recover after an outage and how does it drift (m/1min outage)?
Have you checked the reported accuracy against some benchmark? Accuracy, not what the internal Kalman filter is reporting as estimated error.
For the price
of the systems a real-time 50cm (RMS) accuracy would be already sensational for a moving system.