Ordnance Survey Benchmarks exist all over the country, but the network is no longer maintained due to modern technology like GPS, so slowly they are getting lost and removed.
This form is a called a ‘Flush Bracket’ and 0294 is recorded as exactly 46.7167m above sea level.
Saltburn Station OS Benchmark
Show on map
There was a OS benchmark on the wall of my school which everyone got told about every year in geography lessons.