Sounds good, but you'll probably have to walk quite a long way up Ennerdale on the first evening before you come to a suitable wild campiing spot -- probably beyond Black Sail YHA, which is a fair distance from the car park by the lake.
While Haglofs might be acting according to the law, it sounds like very poor customer service. Unfortunately there are firms which make supposedly top notch outdoor gear which won't stand behind their products, while others go out of their way to be helpful -- often US-based ones, for some reason, Sorry to hear Haglofs belong in the "nowt to so with us" band.
There are some good walks to the south (Dodd Fell Hill and Drumaldrace) and north (Great Shunner Fell and Lovely Seat) of Hawes, and plenty of others very close by. Hawes also has plenty of decent pubs and cafes.
If you're using a tent (as opposed snow holing, for instance) and taking care, there's no reason a down bag will get wet. I'm not saying the hydrophobic down is useless, but I've never missed its presence in several down bags I've used over the years.
Def' agree with Zero. Pricey but worth it. Been wearing all Winter and prob' in Summer too. Rab Meco.
I've got a Rab Meco top which I do like, but for me it's not really ideal for summer. I think it's the 140 weight, with a zipped neck, but it's still a bit warm. The 120 weight would be cooler, but Rab don't seem to do a zipped version.
For "proper hot" a loose shirt is quite possibly a better tool than a close-cut base layer. Something like Rohan's Aura, for example, is light, pretty much sun-proof (SPF 40), has a flash-coating to help disperse and evaporate sweat and also an anti-pong treatment. (Not a personal endorsement, I'm waiting for a plain colour before I try one, but I have other of their "normal" shirts I use and like when it's properly steamy).
For really scorching days I have a Rohan shirt (Overland or Safari, can't remember which) which is excellent when the sun is out, even when there's a bit of a breeze, but maybe isn't so good on the wildly changeable conditions we,ve been having.