For the unseen masses who are able to get an NRF52 SDK14 peripheral to connect to Android but not IOS, the solution was to copy the calls to nrf_ble_gatt_init, nrf_ble_gatt_att_mtu_periph_set, nrf_ble_gatt_data_length_set, sd_ble_opt_set from examples/ble_central_and_peripheral/experimental/ble_app_att_mtu_throughput/main.c...