Thanks as ever chaps ... this is such a good site, I hope that Salmo and noop have got it right, probably have, I'll let you know.
As an additional comment on the stunning world of the internet, I came across another site where there's an enthusiastic garlic grower in the US;
http://barbolian.com/?s=garlic&x=0&y=0I posted a comment about my garlic dilemma and here's his stunningly detailed response, it might help any others that come across this garlic thread:
Hi Roger I see you are in the UK our climate conditions are very similar. It is hard to tell anything definitive from the pictures, but I noticed a couple of things: 1) the main damage on the garlic seems to be in the outer leaves and those are the first to come up and take the brunt of the stress of winter and early spring storms, temperature fluctuations, etc. They often look a little scraggly. No big deal. 2) Very important: the newer growth in the center leaves looks pretty good. They are green, standing tall, and the yellow tips on those are nothing to worry about (in my opinion). 3) Your onion plants on the left look a little beat up! There are some broken stems and signs of stress, which tells me their neighbors (the garlic) probably also endured similar situations in which case, Id say your garlic weathered through pretty well!
What to do: Watch for more changes in the coloring, such as yellowing that extends down the plant in streaks or blotches, especially in the center leaves. For now, I think your best defense is to take proactive measures to strengthen the plant. Now is a good time to apply a little nitrogen. The more strong green leaves it grows now, the more energy it has for producing bulbs later. Personally, I do not use Epsom salts (although I know many people are fans), mainly because of the research and writings of Dr. Linda Chalker-Scott. I would recommend compost, perhaps a little blood meal, or the chicken pellets you refer to, which sound good. In May, I stop the nitrogen and switch to applications of fish fertilizer and liquid seaweed. You could cut off your bottom leaves without harming the plant. As one reader put it, they are not really functioning very well anyway. It might be an area where molds could develop or bugs hang out. That said, I cant say that I have been very good at cleaning everything up.
It is sometimes hard to tell what is disease, soil imbalance, fungal issues, or critters so if you find there are increasing problems down the road, you can always do an early harvest of select plants (you might want to remove a bit of soil around the plant and clean your tools afterwards). One year, I was hit really hard with rust. The bulbs had already had a chance to form, so it did not affect my harvest too much, but I later found out I could have cut off the diseased leaves and reduced the spread.
Here is another blogpost where I addressed yellow tips on garlic.
Good luck, Roger hope this has been of some help and thanks for stopping in to my site. Loved the Allotment Garden site! What a resource and a great way to share experience!