Hi d I’m also in Ireland (East Wicklow) and found exactly the same. No good supply of council compost and came to the same conclusion! I plan to get some cow manure this year and compost that as the horse manure last year worked v well (eventually!) Keep all the old compost bags and use them to collect the manure next time.
I would definitely use the cardboard under the 6 inches to help weeds as it will decompose as the roots grow down maybe just a thin layer though? I found it a life saver last year.
Very jealous of your poly tunnel Im saving up for one!
chris
