The UN nuclear watchdog chief Rafael Grossi is in Iran seeking tougher checks on the country’s nuclear programme. The IAEA faces increasing difficulty in monitoring the Islamic Republic’s rapidly advancing nuclear programme, exacerbated by tensions across the wider Middle East over the Israel-Hamas war. Grossi has already warned that Tehran has enough uranium enriched to near-weapons-grade levels to make “several” nuclear bombs. He has acknowledged the agency can’t guarantee that none of Iran’s centrifuges may have been peeled away for secret enrichment. But the head of Iran’s atomic energy or…