Thanks. I had come up with chard, but dismissed it because I had 'mishandle' as the answer to 15 Ac - the clue being 'Run badly'. Thought there must be another variety of beet I hadn't ever come across! Will have to have a rethink for 15 Ac.
Also must have something wrong for 35 Down - the clue is 'Assertively dogmatic' I have O?i?e?n?t?d but can't come up with anything that fits. Further help much appreciated, especially as these are the last clues!