Not really Prof, when you consider the weight (and value) on two tyres, plus some of the collateral damage sometimes seen with a blow out, £300 seems cheap to me.
Some of the pot holes I've seen recently are more like sink holes!
Kev
I'm concerned that you might be wasting quite a lot of money by going for such frequent tyre changes. I would never suggest anyone weakens good safety habits, but I question if your actually getting any real advantage from your method.
Let's just review a few points.
Unless you are doing very high towing miles and wearing out the tyre or you are driving through very poor road conditions that actually damage the tyre, the vast majority of caravan tyres will be serviceable for upto and beyond seven years. In reality very few caravanner's do enough milage to wear down the tyres to require replacement because if insufficient tread depth even over seven years of caravanning.
There are vehicles on the road that have tyres that carry far bigger loads, so caravans are not exceptional regards individual tyre loads. The tyres have load ratings to suit the weight they carry.
Your caravans weight is not going to increase dramatically, so the tyres you have fitted should be rated for your caravan, and that rating does not derate with time. Tyres are very important, so much so there are checks done to ensure the way they are made conforms to minimum standards.
Bearing in mind the comments above, and how caravan tyres rarely wear out to the point they need replacing except by age, If you cannot avoid a pothole that will damage a two year old caravan tyre, then it will be equally dangerous to a new tyre.
Are you as fastidious with your car's tyres?
I hate to see people wasting money when there is no need to. But also on the case of tyres there is a concern about what happens to those you discard from an environmental perspective.