> You've quoted strike prices at the time
Technically I think the Hinkley prices are what we'd call £2012 [if we could easily write a subscript here I would use that for 2012] that is, they are prices in the Pound Sterling as it was at some fixed point in the year 2012 and so when paid in the CfD contract they'd be adjusted for inflation.
All the early CfD prices were in £2012, whereas those newer CfDs have strike prices in £2024 which is about 40% more money in real terms. You can see this notation in the linked Wiki page.
So, if we adjust all the prices to £2024 that price for Hinkley is about £130 per MWh whereas Solar farms are £75, onshore Wind is £92, off-shore Wind is £113
Except, that's not really what's going on either because those AR8 prices are what's called "Administrative Strike Prices". AR8 like all the other allocation rounds is a reverse auction whose results we won't know for months, and those are the start prices in the auction, if you want to win and you're not the only bidder you will need to come lower. Maybe your competitor says they can do solar for £72, but you stared at your loan sheet and projected sunlight over the next decade and dared to say £71.50, you win that contract. But the strike price is now £71.50 not £75 per MWh. Your competitor might still build their solar farm, but at market prices not the guaranteed £71.50 per MWh you've contracted for. Maybe they get lucky - this summer the CfD "subsidy" for Solar farms paid us back many millions of pounds, because electricity prices were high and the subsidy is effectively a fixed price. Of course this doesn't cancel the hundreds of millions we spend subsidising Drax, but that's a completely different discussion.
Edited to add: Just like a conventional auction there may be no bidders at the start price. Unlike some low stakes auctions you might have seen in person or on TV they don't offer again with a better price, the auction just fails. This happened for offshore wind in AR5 a few years back, the government wanted to pay no more than £44 per MWh in £2012 for offshore wind energy -- cheaper than solar, so the firms who build wind farms looked at their costs and said "No thanks" and there were zero bids that round, and a subsequent government increased the ASP for AR6 wind and got bids at much more realistic prices.