Stocking rate should be around 1 cow or 2 sheep to the acre depending of course on quality of grass etc. This allows for grazing, hay/silage for winter feed and also grazing for young stock not yet in the milking herd. Obviously there will be more cows grazing in a field than I have quoted above but that gives an indication of the size of farm required for a given herd.
Things are looking good Andy, just wish I was progressing at the same rate as you!