[churchman phil]

Don't just jump at the first engineers you find either - shop around. At the place I work, if we require anything made in the engineering sector, the same job can be quoted by two or three different firms with anything up to 70% difference in price from the cheapest.

Part looks like an aluminium casting so a steel replacement should be ideal. Should be easily turned too. Most firms have a minimum order price of around £25 for a one-off job but I'd say around £40 - £50 for the part you want (But don't quote me!!)