UKC

Hi, I currently have a cheapo 3 season Mountain Warehouse bag (not down) which is plenty warm enough for my needs but pack size is ridiculously big.  I'm now after a bag suitable for bivvying UK autumn spring summer that can pack down relatively small. (Weather dependent we will be camping out in the Cuillin October half term). And hopefully the bag won't cost an arm and a leg! All suggestions welcomed

High fill down is usually the best option unless you are planning to get it damp all the time. It does cost a bit, but how often are you going to replace it?

How cold do you sleep? I am relatively warm sleeper* and would describe myself as a decent sufferer, so 400 down fill bag does work all year round, including nights on snow in Scotland with occasional help from whisky and/or merino wool base layers. 

P.S. Keep an eye on what side the zip is located at. I got a left hand one as I bought my sleeping bag second hand when I was a student, but I would happily pay more (not extra!) for the right hand side one since I sleep on my right side and I am right handed. It's not worth £200-300 now to replace it, but one day...  

Thanks, just been browsing similar posts - lots of suggestions, but way pricier than I was expecting.  Think I might go Vango Venom 200 and just wear all my clothes and wrap myself in tarp! 

I’ve been using a Rab Ascent 500 for the past 5yrs and can’t fault it for 3 season use. It’s had a couple of washes but maintains loft and warmth (I’ve been in it & perfectly comfortable for the last 2 nights supervising DofE). 

thanks fozzy, bit out of my price range but it does look a great bag!

the Alpkit range springs to mind

I replaced a huge but cheap bag with a Mountain Equipment Helium 250.    I was in no rush and had no intention of paying list price so just waited until there was a compelling deal.

One of the new ones Tom? How is it?

Some of the second hand bags pop up on various sites - some people use them for Mont Blanc or whatever else and don't need them after that. Sales happen as well, although quite rarely. 

Just be careful as apparently there are some fakes on the interwebs: https://www.ukclimbing.com/forums/gear/beware_fake_mountain_equipment_sleep...

From what I've seen so far it looks fine, but I've not had time to give it a proper test yet.   It definitely packs a lot smaller and a fair bit lighter than the synthetic one it replaced.   I wanted the same warmth for a lot less space in the rucksack and not too much money and it looks like it will do that.

As others have stated, you should look for roughly 400g of down filling. A tad less, If you’re a warm sleeper. 

All the name brands offer such (I have one from Rab). And Cumulus or Alpkit offer slightly better bang for bucks. 

That said, I’ve lately started using a Quilt for summer use (mine is a thermarest,  but other options exist). AFAIK my quilt has around 250g of down and with a good pad, it’s been good to around zero. It’s about half the size of my sleeping bag and lighter too.