Anselm kiefer wishes people wouldn’t fuss over his work. Everywhere his paintings go, curators follow, picking up bits that fall from their encrusted surfaces for conservation. Given that his work now changes hands for millions of dollars, their attitude is understandable. But for an artist whose principal theme is creation from destruction, it misses the point.Kiefer’s art is a conservator’s nightmare. For 40 years it has been getting bigger, more unwieldy and more perishable. Embedded in the paint of the monumental canvases in the Royal Academy’s current retrospective, Anselm Kiefer (until 14 December), are giant heads of wheat, enormous dried sunflowers, sheaves of straw, tangles of twigs, the smashed pieces of a white ceramic sink, books with lead pages, scales