Well, yes, you can grown Vinca minor in just about any conditions! However, even though the nurseries say it is not as much of a thug as Vina major I'd still be careful and doubt that any thing else will grow through...

According to Crocus, V. minor 'atropurpurea' won't appreciate very dry soil, so depends how dry it actually gets. If its going to be in shade, you'd probably be better off with ordinary V minor because the blue flowers will show up better in shade than the purple ones on atropurpureum. As for other things 'growing through it', this plant should have all its stems gathered together, pulled up into the air and chopped off at about 1-2 inches, after flowering is over in spring. Otherwise you just end up with some bare stems running over bare soil (in which weed seeds will germinate) with bits of growth here and there in the surrounding area.

Spring bulbs would probably be OK. There's also vinca minor variegata that would add a lighter touch. There are some ferns for dry shade too Polysticym setiferum is a nice one - if this appeals to you Long Acre Plants have a small selection of good varieties on their website. Some of the perennial geraniums will put up with dry shade too - I persuaded one to be happy by sprinkling gel crystals into the planting hole (It was giving up before this) But I'd avoid the hartstongue fern - that hated really dry shade with vinca when I tried it...

Ophiopogon will take dry shade.

As will Liriope 'Munro White', good in shade

Spring bulbs won't do well in the shade - tulips, daffodils & hyacinths all need sun.

Wild daffodils and hyacinth grow in woodland here Paul. They are fine unless the shade is really dense. The dryness might be more of a problem but tis worth a try.

Yes, they grown in the woodlands here too. However, they bloom long before trees leaf out in Spring, though some bloom on bare wood. Plenty of sunshine still reaches the bulbs.

Thank you everyone. It sounds as though I'd better think again! I bought the vinca 3 years ago and put in a pot to grow on as it was very small. For 2 years it hardly moved and hardly bloomed but last year, although the bloom was sparse, it started throwing out long stems which are trying to get a hold on the terrace. I just wondered whether it would do better in a dark patch which gets virtually no sun, is occasionally muddy in winter but has quite deep cracks in summer. It seems not!
I'm going to look up the ferns, Stera and also Liriope and Ophiopogon, which I've never heard of! Meanwhile , I will ponder the vinca problem again. Thanks for the tip on cutting it back, Bamboo.

Ophiopogon is the plant that looks like a black grass.

Thanks Andrew, I've got a plant of that description that has never done very well---just a black tuft--growing in full sun. Obviously completely the wrong place!

Not at all, Pennyfarthing - Ophiopogon nigrescens grows well in full sun too, but there is a plain green version as well (without the nigrescens bit in its name...)

Oh, well maybe it just doesn't like heavy clay then. It certainly hasn't grown much, but thank you for the info, Bamboo.

It does grow better in lighter soil, an effect I've noticed in two different gardens, one with heavy clay, the other with light and sandy soil, but it hangs on and does spread in improved clay.

Another ploy might be to improve the soil by adding some coarse grit and lots of good rotted compost -that should deal with both the drainage in winter and the cracking in summer.

Thanks Stera and Bamboo. I've just discovered 2 bags of coarse grit round the back of the shed today so I'll add that and some compost tomorrow and give it a try. I'm also keen on the liriope but they only had the blue one at the nursery so will go on looking. Am also going to move one of my two ophiopogon into a corner to see if it will do better there.