Thank you all for your responses. Rosequartz, these look ideal - I have bookmarked the websites & sent queries as to tumble-dryability! Nina, the jdwilliams website is down so I'll check that later in the week - I am going down to see her tomorrow so will be away for a couple of days - I did think that cotton jersey would be ideal, it's wool and artificial fabrics that are the problem.
She's not really fussy about clothes but won't wear bright colours or loud patterns. Unfortunately she has had to give up wearing trousers as she can't get them over her feet! Handwashing/dry cleaning not really an option because of incontinence, there would be just too much. Everything she has is machine washable as until dementia really set in a few months ago she did them herself, but she hung them on an airer in front of a radiator so tumble drying has not been an issue.