OP's links:
{{gwi:351186}}
{{gwi:351187}}
{{gwi:351188}}

missingtheobvious: How do I get my links to be hyperlinks?
If I put my links into an email and send it to myself, the same links are hyperlinks - whereas in here they're not.

Sempervivum cultivar (not "Sempervirens"), likely some form of Sempervivum tectorum, but among the hundreds (thousands?) of similar cultivars, it's hard to say which one.
Most will develop loose form and lanky stems in lower light conditions, which may well be what's affecting yours.

Thanks for the name correction. Regarding low light levels, some of these plants have been outdoors for several years in full sun for most of the day in summer. Maybe they're naturally leggy.

On second thought, given the openness of the rosettes (and long stems) even in full sun, perhaps I'm totally off base... perhaps these are Echeveria? I'd imagine some must be hardy outdoors in your zone 8-ish(?) conditions? Have you seen flowering (so as to compare to the differences with Sempervivum)?

mike, I don't know how much I can help, as I've never used imageshack. In Photobucket, under "share this image," you copy the "html code" link. Is there something similar on imageshack?

What I did in this case was to use a free Firefox add-on, BBCodeXtra, which adds the html code to make things italics, underlined, bold -- and also adds the html code to make an address a clickable link or to insert a photo into a post. Another GWebber told me about it years ago.

So I copied your links to my post, then one at a time, highlighted a link, right-clicked to open the box where you find "Copy" and "Paste," chose "xhtmlXtra" to open another box, then clicked on "URL."

Here's where you can find BBCodeXtra:
https://addons.mozilla.org/en-us/firefox/addon/bbcodextra/
===

Whatever you see in Preview is what folks will see in your post. So if the photo's not there in Preview (or something else isn't what you expected), it won't be correct in your post.

You might also want to go to GW's Test forum (which is listed on the huge forum list). That used to be a place where you could ask about posting issues, try using html code, etc. -- though I'm not sure what it is now. Anyway, you could ask there and see if the knowledgeable folks are still showing up to answer html-type questions.

missingtheobvious: None of the Imageshack codes worked in here (maybe it's just me!), but I tried BBCodeXtra and it worked a treat. Thanks for that one.

abgardeneer: Both types belong to the Crassula family, so it makes identification harder. It does closely resemble Echeveria puvinata, but the latter has hairy leaves, whilst mine is smooth. Also, the Echeveria family is stated to be frost tender (min 41ðF). We're in roughly zone 9. As for flowering, you'll have to wait until next year!

with these plants...

unless you BUY A NAMED VARIETY ,... from a reputable source ...

you might never know.. with certitude.. what it is ...

as i like to say with my hosta... a $100 plant.. without a name tag.. is a 5 dollar plant ... lol

so if you want to collect.. start collecting them.. already named...

this is one of my favorite family of plants for sharing.. everyone has extras.. and wont mind if you take an offset .. and you will always be able to break off a piece .. to gift a friend ...

ken

Mike - I'd look at Aeoniums. In a London garden microclimate some can survive outdoors.

To me...this looks like Sedum palmeri. It will have yellow blooms. See link below for a plant pic.

Here is a link that might be useful:

Sedum palmeri certainly looks like it. But my wife says it has delicate pink flowers, not yellow. (she could be mistaken!). It looks like I'll have to wait until it flowers again!

Thanks for all your suggestions.

My wife says she may have been wrong - the flowers could have been yellow!

Well, Winter has passed and Spring has arrived, and here's what the flowers look like:

http://imageshack.com/a/img35/4403/t8gm.jpg

This post was edited by mike_jw on Tue, Mar 18, 14 at 13:20

Yes, I still believe it is Sedum palmeri. Thanks for coming back with additional pic!