Well theres the result.

http://www.bbc.co.uk/news/uk-england-bristol-11795116

did a He177 come down in Norfolk?

Rocketeer.
At the moment I am reading Norfolk in the second world war by Neil R Storey. Just got to chapter 4

Quote: On Saturday 21st Oct 1939 a Heinkel He 115B from 1/Kustenfliergruppe 406 crashed into the sea 5 miles off Spurn Head Yorkshire after combat with RAF Hurricanes of no 46 squadron. All the Luftwaffe crew were killed and their bodies were carried by the tide until they were washed ashore at Mundesley and Happisburgh Norfolk. They were buried on 2nd Nov 1939. End quote.

A few years ago a cargo ship somewhere in the north sea, lost several containers off its deck in rough seas, one 20ft hazardous chemical container on its trailer was washed up on the beach at Cley next the sea, Nth Norfolk.
So I am thinking that If your wheel was just found on the beach, then the aircraft may not have crashed off the Norfolk coast, but could be anywhere off the east coast of England above Norfolk.

Quote: Weds 6th Dec 1939 Heinkel (He115 float plane (2081) from 3/Kustenfliergruppe (Maritime group)506) on a mine laying mission flying across the wash to Sheringham. The Heinkel collided with the Chain Home Radiolocation mast at West Beckham, narrowly missed the Sheringham gas holder and finally crashed onto the West beach a short distance from the lifeboat house at 3.15 am. End Quote.

It goes on to say locals salvaged what they could until a guard was placed. ( The pilots seat was used in a fishing boat.) the plane was cleared up, and the petrol tanks sent to Farnborough as they were self-sealing type.

Bumblebee. This teenager got into trouble for wearing a poppy.
But good on her, she has stood up to her beliefs.

http://www.bbc.co.uk/news/uk-england-hampshire-11708637

sure were pricely melons

Forgot to tell you where I found pic.

http://www.raf-lichfield.co.uk/No%202%20M.T%20Gallery.htm

could it be part of a vehicle audible warning device ie a Horn ?

Think you could be right roadracer.

Above M/40 is what looks like the object, with a wire or pipe running into it from the side.
Other pics of these trucks don’t have this object on them.

Ok only a guess but could it be an early type of this?

I have searched for a pic of Rear of RAF vehiciles, but can only find pics showing fronts.

Nimrods for sale. Would you believe it on here.
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=190458901355&ru=http%3A%2F%2Fshop.ebay.co.uk%3A80%2Fi.html%3F_nkw%3D190458901355%26_in_kw%3D1%26_ex_kw%3D%26_sacat%3DSee-All-Categories%26_okw%3D190458901355%26_oexkw%3D%26_adv%3D1%26_udlo%3D%26_udhi%3D%26LH_Auction%3D1%26_ftrt%3D901%26_ftrv%3D1%26_sabdlo%3D%26_sabdhi%3D%26_samilow%3D%26_samihi%3D%26_sadis%3D200%26_fpos%3DPostcode%26LH_SALE_CURRENCY%3D0%26_sop%3D12%26_dmd%3D1%26_ipg%3D50%26_fvi%3D1&_rdc=1