It used to be "Rip Off UK" years ago
I agree - but to be honest a lot of stuff is currently very reasonable compared to other countries that used to be much cheaper.
I noticed a big drop in prices after the recession hit - the opposite to the USA where almost everything (other than house prices) seems to have gone up since the recession..
Right now, I'm in California and one of my colleagues takes his car to a back-street garage for oil changes and repairs - it's US$95 (£60) per hour but in my local area in Scotland (Galashiels) a back street garage is probably only £35~40 per hour at the most.
I also thought the price to swap the crankshaft was pretty reasonable but as it should have been fixed by KIA under warranty (it's a factory defect) I was pretty pi$$ed off at the time - especially when I told them what the problem was and they kept telling me otherwise!
It might be time to think about a different brand of tyres for your van - over here in the USA it seems quite normal to get 40~50000 miles out of them. The Sedona/Entourage is mainly available as the heavier LWB variant so there's no reason for terrible tyre life. As an example one of my mates has a Mitsubishi Warrior that had a set of BF Goodrich tyres fitted - they lasted 80,000 miles
I think he had 2 or 3 sets before he discovered that price isn't always the best way to look at buying tyres.
Tyres in general don't seem to last anywhere near as long as they do in the USA - maybe it's due to the different types of roads or just much softer compounds? Perhaps you need the tracking checked - or is it even wear?