I discovered a large number of these grubs in my flowerbed.
Should I be concerned? Can anybody identify these?
Managed an ID based upon your hints. It's a Merodon equestris larvae. Commonly known as the Large Narcissus fly.
It's a bulb pest but I'm not sure I mind.
The image that lead to the ID is here: http://www.bugsandweeds.co.uk/hoverflies.html