Reply To: found an air rifle under my shed. ..
As far as the Ft/Lbs restrictions in the UK, I cannot speak to them (living in the US), but it is definitely possible that a .177 could produce 12+ ft/lbs. My .177 Hatsan 155 puts out a low functional range of 23.32. That being said, you may need to call in an expert to reduce the ft/lbs to an acceptable level for your locality, either by modifying the air outlet or by installing a weaker spring. If it purports 12 ft/lbs and is .177, it’s likely a model designed for the US market.
As for the cleaning pellets, I would not recommend them for in-depth bore cleaning. They work OK for routine maintenance (I run 3 through the barrel every hundred shots or so), but they don’t have enough abrasive force to remove rust and caked-on fouling. Better to go with a bore brush and some non-imbedding cleaning paste.
Keep us updated as the project proceeds!