Thanks for the advice and suggestions - much appreciated - and will be acted on!!
In reply to the question 'are they pedigree'? The answer is that the younger of the two sows is from the Barnsnap herd, however she is not registered. The older sow is certainly an OSB but her history is obscure. I got bought her from a smallholding where she was being kept in miserable conditions. The boar is registered.