Wasn’t thinking of camping on the airfield, but would just walk out to the coast and pitch the tent among the dunes. If you look on Google Maps satellite view you can see the sort of land I mean, and I doubt anyone is going to bother you there.
Careful of the naturist beach that appears to be near the threshold of 35.
If you want to go up Snowdon then Caernarfon is nearer than Llanbedr. I have been up a few times, once having flown to Caernarfon through IMC over Snowdonia at about 5,000ft, somewhat bumpy, and then a cloud break over the sea with the ceiling at about 1,200ft. Not one of my smarter moves.
Peter, just learn from the pros 
(amazing in flight shots of a plane from a drone buzzing around it)
I am reminded of the paraglider who was caught by a Northumbrian farmer whilst wrestling with acres of fabric in the middle of a field of cattle.
Ee man, you canna camp here!
I did another “camping test” last night and had to capitulate when the OAT fell to about +3C
Clearly one needs a lot more serious kit for that. The sleeping bag is rated down to -6C but everybody knows these ratings are nonsense.
At say +10C it worked great.
So it’s quite a good solution for a dodgy marriage, but only in summer
Just my small experience : I have this sleeping bag
https://www.snugpak.com/outdoor/softie-elite-984 combined with this mat https://www.snugpak.com/outdoor/accessories/self-inflating-maxi-mat
And I slept in it within a tent down to about -2C. I had many layers on me.
With your new tent and sleeping pad I am surprised that you had to capitulate. That being said, +3C can feel pretty cold if your sleeping ‘system’ is not quite right. I once tried to stay out (in the summer) with no sleeping bag and just a bed of spruce boughs. I lasted about an hour. I then descended the mountain to warmer air and tried again. I lasted another hour and then decided to hike out with my headlamp. I won’t intentionally try that again.
I have a negative 3C sleeping bag and I find it works pretty well for summer mountaineering (usually it freezes overnight at elevation). It is no longer sold, but is similar to this: https://www.mec.ca/en/product/5035-436/Talon—3C-Down-Sleeping-Bag . I occasionally find it cold if I don’t have a tent, or if I am using a thin pad to sleep on, but that does not seem to be your situation. This sleeping bag turned out to be so good (800-850 fill down, total weight about 750g) that I gave my -6C bag to my brother and have never missed it.
Was your sleeping bag down or synthetic? Some of the synthetic bags get flattened over time and are less insulating. Also, depending on how cold it is, you really have to zip up the mummy bag hood around your head and may need to leave some clothes on (say a hat and thermal undies).
Here are some pics for fun.
Although, I do recall being pretty cold on this trip in China. It was an ultra-light summer trip and I only had shorts.. A cold storm blew in and we huddled in a Great Wall watchtower overnight…
WOW you are one serious camper
The sleeping bag is down. It is a good one – here. We already had it. I was wearing indoor clothes inside it, not the whole outdoor stuff which would obviously have been much better.
The MSR Elixir 2 tent is impressively good compared to my previous (limited) camping “experiences” but I can see you do get what you pay for. It is really easy to catch the cheap zips on the edges of the fabric and jam them. Easily done in the dark. This is a common issue with clothing and I never buy anything with cheap zips. Watching the videos of the Hillenberg tents shows much superior zips. But this will absolutely do for what I want.
Sleeping bag liners might be an idea? Either silk or fleece?
I never got on with liners. I have a silk liner and it is a bit fiddly and bunches up and wasn’t particularly warm anyhow. The idea was that I could get a lighter sleeping bag to use plus or minus a liner, rather than having a heavy sleeping bag and a lightweight one. It was an idea that appealed to a poor student..
Peter, that looks like a pretty good sleeping bag. At least the specs look similar to mine (they both have about 400g of down), which I really like on a weight and size vs warmth matrix. I think you will be fine once the temperatures come up a couple of degrees. One factor that I did not consider is that I am very rarely alone in my tent, so an extra person probably adds a few degrees of warmth. Come to think if it, for most of the solo trips I have done I was using my old sleeping bag which was rated for a few more degrees of warmth.
Happy camping. A few more pictures below, which could be considered in an aviation context – it is my goal to own a ski equipped aircraft and fly right to the base of mountains. These pictures are from the South Patagonian Icefield, of which I was fondly reminded of from Terbang’s trip report.
