In reply to fire_munki:
Firstly, it depends on your priorities. If bike packing I presume you would prefer to take something that is is light and packs down small. In this case a down bag may suit you better than synthetic, especially if campsite camping. Half the weight, much smaller pack size but ( sorry ) double the price. For car / van camping size and weight probably don't matter so synthetic would be fine. You may find a Vango bag suitable, they have some cheaper down bags. If weight and packed size is a really high priority have a look at the Ultralight gear website for a wide range.
Another aspect is ensuring you have a decent insulating mat underneath when camping, again you would probably want to go small and light for the bike packing but think luxurious for car / van camping.
Temperature ranges are a rough guide but not that accurate or helpful because we all sleep very differently. So many factors involved including what exercise you have done, what you have eaten and drunk, what you are wearing, the shape and sizing of the sleeping bag compared to your shape and size, the nature of your camping spot ( windy, cold hollow, protected ) etc. Also UK summer spring temperature range varies hugely.
Of course, none of the above really helps you. So my suggestions would be:
- Go for a 2 season mummy shaped down bag ensuring it fits your height / chest.
- Go for a lightweight inflatable insulating mat ensuring it fits your height / chest.
Good luck.
