For the lamb's horn, wobbling around it will be painful and annoying so Shep's advice to remove it is good - by yourself or by the vet. They bleed a lot as there is an artery in there so don't cut anything fleshy or stringy. The blood on the wool will attract flies so trim it back. The horn is very close to the brain so you don't want infection getting in. We have used (clean) cobwebs on bleeds and they work very well, but you must keep the flies off.
What breed are your sheep? We went for many years without using an anti-flystrike spray because we are on a windy hill, but then one year our neighbour's sheep were struck and were dying beside our fence (he's not allowed to keep sheep now) thus attracting flies which attacked our sheep too. So since then we have used Crovect each year (and planted biosecurity hedges) - fly strike is a truly horrible visitation.
Not being irish I have no idea what a clatch is. Could be like a clutch as in a lot of eggs (larvae), could be a skep or beehive, could be the bit the honey is collected on (frames? - I'm not a beekeeper) or could be anything. Language in the UK is all about dialects, especially in country areas. Shepherding terminology varies greatly throughout the UK and boggles the mind

. I come from England originally but live in Scotland and have moved around quite a lot - each move and I have to understand a new dialect and I find people in the new area don't understand words from the previous area (or my English accent). Then there's Gaelic - you'll find one version in Ireland and probably as in Scotland, each area will speak it just that little bit differently.
There's a wonderful clip in the archives (BBC probably) of 'The Man from Strabane' being interviewed about something - not a single word is intelligible to anyone not from Strabane, but we all love listening to it