It is indeed Duchess, ex Albury Park in Guildford. No. 15466

It wasnt rotting when I last stood on it. It was nicely sheeted. But as noted, it isn't that one

Roxton Park Steam Rally 1970
 

Thanks to everyone who has suggested IDs.
I believe it should be Bill Colebrook (no 'e') and that makes the ploughing engine 13880/1917.
Can anyone confirm that the Saunders roller is then Fowler 17560/1929?

It's worth bearing in mind that very few engines were roaded in the '70's, far fewer than today, and those that were didn't go very far.

Yes it is

Roxton Park Steam Rally 1970
 

Thanks.

Apologies for being a bit late responding to this one, Fowler 15466 is safely tucked away in a shed not a million miles away from me, photos did appear in Old Glory July and October 2009 in John Crawleys column 'early preservation files' showing her on strakes and painted maroon as in these photos.