The CBA fairy has made her way here, so cheese on toast it is.  We had so many plans but the weather has thwarted all of them. 

 It's been raining nearly all day and it's chilly 

 got it on the last one 

Rats love to live somewhere they can always get water, so allotments are popular because of all the taps and waterbutts around.  I worked in garden centres for quite a few years and you always get them there because of the same reason.

Our site has no chickens on it, but we still get rats around.  Luckily we are surrounded by houses and there a lot of cats that patrol the site, so they never get too out of hand.

I’d agree with John that breaking the tunnel up where you can get to it without disturbing the asparagus may well work.  You will need to keep doing though until they get the message.

Thanks for the responses !

I took the plunge and planted out half the crop this morning, dibbling all of the holes before fetching the leeks, so minimising their exposure. All now covered in mesh, time will tell !

Leeks on a neighbouring plot have been fine, while elsewhere on the site, catastrophic attack. It all seems very random.

A benefit of purchasing the micromesh is that we now a a bit left over, enough to protect a small carrot bed This could be the first successful set of carrots since taking a garden here about 15 years ago.