Hi there Toffeeapple & thanks for your welcome.  I thought I had just clicked on the smiley (a thumbs up, to be precise) and it looked fine when I went to post it...  Think I'll go back to the test forum and practice...!  Thanks for offering to edit my post and replace the tekky text with something more meaningful,  that would be great  (will now click on a smiley face and hope for the best)

Thanks for all your welcomes, I'm very pleased to be joining you all!

Kate, thanks for your honey fungus advice.  Unfortunately I think we do have the real mccoy.   I'd been a bit of an ostrich when it came to working out why there was an increasingly strong smell of mushrooms in the soil...  Where it appears to be rife is a south-facing bed where we had removed a number of  eucalyptus shrubs two years ago.  When digging the soil this spring we found that the remaining eucalyptus's roots (together with the mint & parsley's) were covered in the white fungus and there was a lot of fungal fibrous bits in the soil, which I think were the roots that we hadn't managed to remove previously.  It was a well-cultivated bed (we grew potatoes in it last year) and that has helped the fungus to spread.  In the other bed where it appears to be, we had removed a sapling sycamore as best we could six years ago- but knew there were roots extending under the growing shrubs, fence etc.  It's a heavy clay soil bed that we've not really cultivated as it's well populated with shrubs, but I was aware of an increasing mushroomy smell.  After excavating a little last weekend I discovered that it's well & truly got its claws into the roots of the ceanothus and another large variegated shrub.  Unfortunately it's got more scope to spread, as across the path from that bed I had a leylandii hedge removed last year and there are many roots left that go under the path and the lawn.  I treated them with roundout stump remover, but I gather leylandii are particularly susceptible... I'd left that newly-created bed empty, as I wanted to monitor it (having suspected that honey fungus was possibly already present, I'd emailed the RHS for advice on what to plant as I wanted a lavender hedge and they basically said sounds like you've already got honey fungus, so don't plant lavender...).

The challenge now is containing it to those two beds and protecting the other parts of the garden... Have got some fish pond liner to form a barrier to the 'bootlaces' and am gemming up on plants that are more resistant (that said, eucalyptus wasn't on the RHS list of susceptibles).  Am also doing the wood ash 'tonic' from another blog that fiona mentions on her honey fungus post (though I suspect, unlike humans, honey fungus isn't susceptible to the placebo affect!)

Has been fabulous gardening weather though (wish I were there now..)!