Complex sentence: Since the "tank" was a British concept it is more likely the Hornsby, which had been built and unsuccessfully pitched to their military, was the inspiration, as some claim it also was for the description of "caterpillar".
Split into simpler sentences: Since the "tank" was a British concept it is more likely the Hornsby, which had been built and unsuccessfully pitched to their military, was the inspiration. Some claim it also was for the description of "caterpillar".