The Bahco wide jaw smooth jaw spanner was about the only one like this on
the market. It opened out very wide and a short handle. S/fix number:
38428 It is £18.47

I have one of these and it is very handy indeed especially for 28mm
compression joints.

I notice in a tool stall a cheap maker doing a clone for £7 to 8. Am-tech
Stock Code: C1678.
http://www.avenuesupplies.co.uk/index.php?id=900

http://cgi.ebay.co.uk/2-IN-1-WIDE-MOUTH-WRENCH-BRAND-NEW_W0QQitemZ220158741051QQihZ012QQcategoryZ20774Q QcmdZViewItem

It also comes with plastic jaw covers for chrome joints. The Bahco is
slightly slimmer and gets in tighter. The Am-Tech has a larger adjusting
wheel, so easier to adjust. I bought the Am-tech to supplement the Bahco
and it is well worth the money. The Bahco is way over priced IMHO. Mine
rusted on the jaws after a few days. It needs constant oiling to prevent
this, as will the Am-Tech. For over £18 I would expect a chome rustproof
tool.