Complex sentence: Substantial portions of the lines still survive today, albeit heavily decayed due to locals re-using 100,000 tons of stones, although some conservation and restoration work has been undertaken in recent years using EC funding.
Split into simpler sentences: Substantial portions of the lines survive today, albeit in a heavily decayed condition due to locals re-using 100,000 tons of stones. Some conservation and restoration work has been undertaken in recent years using EC funding.