Shane,
Given your circumstance i.e lack of time, lack of good compost available, yes I think that is a great start. I’ve done exactly the same as you, as I’ve suffered exactly the same constraints.
Okay, its not real compost as a purist will quickly point out to you, but you have a living to earn, taking you away for long periods from your allotment. However, have a peak under your cardboard in 4 weeks time and I will guarantee it is still reasonably damp. Only today i saw one of my neighbours busy digging his allotment, and he felt really good about it, not realising that all he was doing was drying out the top 200mm of soil! You, I guess are not in a position to water on a daily basis. This time last year we had no rain in london for at least 6 weeks, so for this reason alone you are on to a winner!
I am working on my committee to try and get a petrol driven shredder to chop up fresh staw / manure so it composts quicker….
BR
Neil PS where in London are you?
