Hi Nigwill, anything that is not dairy or meat based basically... and plants which might spread soil disease.
In real life I think all is as before for personal consumption. As far as I'm aware there are no searches of motorhome fridges and cupboards. Even if there were and you were carrying something against the rules/law you may get it confiscated. Never heard or read of it happening other than some ham sandwiches that the media jumped on when it was a new situation.
Personally I will carry whatever I normally would and 'risk' having it confiscated by an over enthusiastic customs officer.
Officially I wouldn't advise anyone to break the rules
Pretty sure sauces and things are not restricted unless they are meat or dairy based.