UKH

Just looking for some recommendations really. Something I can use for 4-5 hours and bright enough to illuminate some boulders. Thanks!

This (or the 10W version) is the standard recommendation: https://www.screwfix.com/p/diall-led-rechargeable-led-work-light-23w-12-240...

I should have said, you want two of them to reduce shadowing. Fortunately they're pretty cheap.

Great. That's perfect. Thanks!

Back in the 80s we used to go night climbing on Southern Sandstone and used industrial gas lamps like the ones the Gas Board use for night time mains repair work. Very good at floodlighting the rocks, although you did get shadows when they were pointing upwards. We overcame that by also using head torches to illuminate holds.

When I lost my trusty Petzl Tikka, I bought a Ledlenser MH6. The Tikka was compact and reliable, but not rechargeable, and sometimes, especially in the rain, it had a noticeable flickering. The MH6 is rechargeable, the light beam is stronger and not flickering, but it is a little more bulky and has a tendency to switch on by it self in the backpack.

Funny you say that, I was specifically thinking of some late night Fandango sessions

As above, these are great for lamp sessions and DIY. They last longer than the advertised battery life and I have never felt the need to use the higher power setting. 

I find that just using my phone's torch or perching a headtorch is enough to prevent shadows if you don't want to carry two lamps in.

I have also seen a lamp from Lidl or Aldi (I forget which) at crags which is just as bright, smaller so easier to fit in your bag, a similar price, has more mounting options (with the Diall, I use a strap if I need to attach it to a tree) and also functions as a battery pack for charging other devices. I don't know what it's battery life is like though or whether it is still available or was a time limited product.

None.

It the use of spot lights that rightly pissed the farmer off at Almscliffe and stopped night time climbing.

Some of us had climbed there by head torch for years until this new inconsideration of spot light use screwed things up.

Small head torch and think of others

There is nothing wrong with using a lamp at the right time and the right place (Almscliff not being the right place). There are plenty of crags where you can have a lamp session and nobody other than other climbers would ever know you were there.

Using a lamp obviously requires careful consideration of other people (including never in view or earshot of houses, never anywhere with sensitive access etc) but there are plenty of suitable venues.