Thanks. is it best to stick with wired?
Wired will always be better for any given budget. Bluetooth requires a bunch of electronics that wired headphones don't need. Those cost money, so everything else must be cheaper. In short, £40 wired headphones will sound better than £40 Bluetooth ones, purely because more money is spent on what matters.
You usually have to pay more for Bluetooth headphones compared to wired to get the same or similar sound quality. Bluetooth headphones with a RRP of £40 aren't going to be particularly good, such as the Soundblaster JAM on Creative's site. The other two (WP380 and 450) have a much higher RRP; around £100. Meaning the quality won't be skimped on as much as the JAM's.
Even so, with around £100 RRP, user reviews for the WP380 and 450 are somewhat middling on the jungle site.
If we take AKG's Y50BT headphones as an example, they have an RRP of £120 (similar to the Creative's), but the sale price is around £100. Why can Creative sell a £100 Bluetooth headphone for £40? Possible that the RRP's were inflated to make them look like a more expensive better quality headphones? Looks good against the promo price of around £40. Just a thought.
As for the £80 RRP of the Aurvana Live! compared to the actual price of £40. They did cost that at one point. Been around for a few years now and are based on Denon AH-D1001 headphones. A price drop on older headphones is much more expected.
I think unless you really need Bluetooth and want to wear them walking around the house listening to music; for use in bed connected to a tablet, at this budget I'd stick with wired.