Does anyone know where to get some truck airhorns that sound good and don’t cost a fortune preferably connection through 24v rather than air,looked at some on Internet but would like a company that’s recommended by another trucker who might have used them any info appreciated
I bought my small set of airhorns at Rigs & Twigs, which I see are still in Bristol. They were proper air but with a proper compressor they work well.
Pop into J13/M1 truckstop , theres a truck accessory shop there in a portacabin .
M1 south - exit J13 - 
turn right - truckstop on your left hand side .
or
M1 north - exit J13 turn left truckstop on left.
You can at least have a wander around the shop and get an idea on types and prices if nothing else .
Look for Stebel air horns on YouTube.
Had a set on my 12v recovery truck… moved the traffic on the way to police jobs no problem.
Got them off eBay, they do a 24v version too.