We're clay here as well and our gateways have been put in their places as it seemed the best place for them! I did have 1 moved last year as at the time of installation we never took into account the wet, considering it was on a bank we never thought it would be a problem! Now it's On lower ground and doesn't get wet, weird that. Similarly, a neighbouring gate (on same post) is 14ft and after Junipers escapades last year and mum "helping", it's never been the same!
I couldn't drive to roll it flat, mum "I know what I'm doing" when I told her not to go uphill, 10 minutes later, phone call "I'm stuck, bring zetor to tow me out!" Never going to happen ! Our roller is old and solid concrete and wedged tight!
Couple of hours later neighbour and manitiou with chains rescued us. Then I let him roll the bank. After all, if it's going to happen again, it may as well happen whilst help is there. Currently, gateways not too bad and all cattle and sheep just wandering . . . .