Xgody off Ebay - Chinese thing, dirt cheap but no live traffic and uses stolen maps so wont be bang upto date (have read can be 12 months behind). Not 100% sure ifbtuey run off 24v.
Tomtom Professional 6200 - most expensive but includes live traffic built in (no phone req), and map updates at least 4x a year.
Tomtom 620 professional - same as above! but needs to bluetooth to a phone for traffic.
Tomtom car nav - works well but doesn’t know about low bridges and weight limits. Some have live traffic. Can be a tad stressful when you go down a road and find a low bridge but more suitable for certain areas like Cornwall. Also check charger can run on 24v.