Rangers striker Cyriel Dessers cut a frustrated figure when he was subbed off against St Johnstone on Scottish Premiership duties. The big Nigerian striker, 29, missed a golden chance when he saw his free-header loop over the St Johnstone net in the first half. In a moment, it somewhat summed up the frustrations Rangers fans have had with Cyriel Dessers. Frustrations they’ve had no trouble in espousing. A thoroughly likeable personality at Ibrox, Dessers has blown hot and cold over his 15 months or so in Glasgow with the number nine jersey often weighing heavy on the hitman. And that inconsist…