I don't think it sounds right for Red-throated Pipit (cervinus), though it can be difficult to judge single calls from less clear recordings. It sounds too modulated to my ear, and therefore in the ballpark of a Tree or Olive-backed Pipit. Regrettably, due to some degree of overlap in these buzzing calls, and as you say that you generated a sonogram and it was unclear, I wouldn't like to proceed further.
It is a pity that this bird didn't give any audible sip type calls, those of Tree being noticeably lower in pitch than the equivalent in Olive-backed. Living in migrant-impoverished Ireland, I lack the regular exposure to Tree Pipit that most European birders can easily attain, though I do know that these calls, if given, are very useful.