Hi Rans, if you sign into the Met Office website, you can get all the recent European METARS, or the local UK ones.
Although the Temperature - Dewpoint calculations, using the lapse rates, are theoreticaly correct, and used as exam questions. In practice they are nearly always wrong....
Trying to work out Cloudbase from T and DP will give errors. It is possible for Temp=D.P. and have CAVOK or NSC.
Also, from the Metars, you may see an airport with 'Few at 3200ft' and 18/16, which would have given a cloudbase of 800ft, if you had used the formula.
However the calculation works backwards quite well... IF there is Fog or low cloud, then the Temp will be the same as the D.P.