OK, reporting back some with results and thoughts for reference in the future....
Took the car to Kwik Fit because they were the closest to an underground station en route, and opened from 8:30am onwards.
Left key with them and they said they would call me once they did check.
3:45pm and still not heard anything from them, so I gave a call. They said that they couldn't see any punctures, and only then asked me for more details.
Note1 : Always call them earlier to check in! Could have returned to them after work only to find they did nothing! They then agreed to lift up the car again and specifically check the valve, and call back in 15mins. They did call, confirming a leak and they could try to repair the leak. Cool. Quoted £27 to do this, to which I agreed.
A few minutes later, they called again. They took the tyre off and found a small screw INSIDE which had damaged the inner tyre. They asked if I had driven it around a lot with a flat tyre. I confirmed yes, and they concluded that it would therefore be beyond repair, and need a replacement.
Note2 : Always try to check into a garage ASAP if you spot a flat tyre - repair might be possible, but not after 20miles driving to a beautiful park in Surrey and back again!So I then asked them what options I had for tyre replacements. Having done some research, I was quite confident I knew what I wanted and the prices to expect.
Me: "So what options do I have?" expecting them to introduce all-weather or Winter tyres
Kwik Fit: Well, the only thing in stock that will fit is the Bridgestone ER370 for £120."
Me:
. "Nothing else? What about the Michelin CrossClimate tyres by the door?"
KF: "They're not the right size for your car. And you'd need to order in advance for those to be replaced four at once."
Me: "Oh. And how much do those cost?"
KF: "£120 including fitting. Same price as the Bridgestones."
Me: Sigh.... "OK, can't do anything about all-weather tyres now. Let's just get that tyre replaced with the Bridgestone one."
Note 3: Always do your research on contingencies IF they need to do a replacement, would that have your ideal tyre in stock? Are you prepared to replace just one, or several at a time?Note 4: The costs that I've seen on Tyrereviews.co.uk are only £70. But don't forget that there are additional fees eg £15 fitting, as well as in-stock mark ups for these garages, which in my case turned out to be £35. Are you prepared to pay that extra for immediate access? Or are you willing to take a chance and DIY it or run on flat tyres until you're at a cheaper garage?Note 5: If you still sticking with Kwik-Fit, you could save £15 fitting fee by ordering it online.So, in the end, I now have a Summer tyre replaced with another summer tyre. No change to all-weathers which I was hoping, because the garage had already ripped off my broken tyre and declared it totally unfit for re-use. If I had stood fast with NOT replacing it and decide later, then I might still be able to decide how to replace... however, Kwik Fit scared me somewhat by saying that my tyre might blow out because the tyre's damaged, and that would make the care lose control. Not something I want to experience in cold rainy weather!!
So what will I do about the forthcoming snowy weather predicted? I had previously ordered from Amazon.co.uk some "snow socks" that wrap around the front tyres (because that's where car's efforts are) and they will help for temporary situations. I would have preferred to install all-weather tyres, but maybe next season.... and prepare it in advance!!!