I was paying £9.50 until quite recently, I hear what you're saying. But compared to C/F HMR is cheap.
Not if you reload and keep an eye out for consumables cheap on here, excluding brass and my time I'm loading .223 for 25p-30p a pop, hornet for the same, 6.5 x 55 & .308 for 40p - 50 p a round. HMR locally is as much as £25-30p so really not a lot in it. I also have control of the quality of my ammo which as we all know is the main issue with HMR.
to the OP, if noise is an issue .22 with subs is a cracking round, (not literally), HMR. Will but you another 50-70 yards but is noisy. If you get the chance then get both, accurate .22s can be picked up for £<100 so needn't break the bank, but SERIOUSLY consider the WMR over the HMR. If you're prepared to / interested in Reloading then go .22 and one of the hornets....
If you want to shoot all uk deer then you need the .243, whose to say you haven't got previous experience already and therefore it's too big? But I'd go swede instead
, you all seem to worry about experience, you need to come over here , at least once a week I get asked about which round they should use, as in which one fits my gun, I think there in a blue box ?,no wonder we have so many shooting accidents.