Temperature Gauge in 110

[touching cloth]

Does anyone know if the temp gauges are the same across the board or differ to match up with sender from engine type to engine type (I am guessing and hoping they are). When I got my landy I had no output on the temp gauge at all, it jumped into life however when (on advice from friend) I earthed the cable, so we diagnosed a faulty sender. Bought and fitted a new one of them and now do get a reading on the gauge but stops rising at the first mark, 40. So next I thought faulty thermostat, except taking a temp reading off the block (using infra-red thermometer thingy) near the temp sender gives a reading of around 70 degrees so engine appears in fact to be getting up to temp, certainly higher than 40. So now I think about it the gauge I have is slightly different to the others (clear backlit rather than green) so I am now wondering if someone tried to change the gauge before thinking it was that that was broken and not the sender, but then used a gauge from the wrong type of landy pss a diesel as mine is A V8, hence the gauge and the sender aren't correctly calibrated to each other.

Any musings, advice and knowledge much appreciated for a mechanical numpty.

[touching cloth]

Excellent thanks