Immigrationboards.com

How easy it is to count number of days outside for EU national as their passport don't get stamped like someone under UK immigration roles

if someone travelling 6/7 times every year for business/family reason inside the EU

6 * (no of days out of UK) or 7 * (etc).

It is pretty difficult to be absent for more than six months per year without noticing. Of course, there will be those who are borderline and would need to be careful.