lambda oxygen sensor

[Andrew Linkens <alinkens@nuera.com>]

I'm thinking of installing a lambda oxygen sensor with a gauge under the
dashboard to constantly monitor the oxygen in the fuel mixture. 
1) Has anyone on the list added a gauge - if so have you any details please?
Also, are there places that sell the sensor in the UK? 
2) How easy is it to attach to a standard cast iron manifold?
Andy
'69 Vitesse
'76 2.5S Estate