Window winders

The security blinds have winding handles on the inside. The highest elbow fails randomly. It's a cast aluminium part. You can't buy the broken bit, or at least I can't find it. 

The main pole is 12.4mm OD, 9.3mm ID. 

I found 2 handles that fit. 

Part no SMF321A is marginally cheaper (10€) and is fully aluminium. I've fitted that in the bedroom where it will be used a lot, but on a small blind. 

Part no SMF301A is practically identical (10.70€) and is steel except for the same alu casting to the pole. 3 of these were fitted to the largest blinds. The remaining 3 are original and in the remaining bedrooms.