My 94 Cally starter is not very old, its a valeo D6RA Ive google that and found…http://www.ebay.co.uk/itm/S898-NEW-STARTER-MOTOR-VAUXHALL-ZAFIRA-1-6-PETROL-D6RA32-D6RA62-D6RA93-/130846412058?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item1e770dcd1aAny Input???
think that the car ones spin in the opposite direction. I did find a place in essex that supply all the replacement parts for our starters.
Pulled the end covers off mine, the armature is seized solid, the solonoid is throwing the gear forward but no spinning? I am reluctant to strip it, though Vermiere had a similar fault and his magnets had fallen off jamming the armature.I have a place, Elliot Pinder, in Cinderford who have rebuilt many starter motors for me, I may whizz it up there.
Magnets falling off is common.
My 95 Cali was fitted with Valeo D6RA21 starter that died 
I found a local supplier who got me a pattern one for £111 delivered Supplier in Scunthorpe was WNS Electrical Ltd and ask for Aidan - top bloke
Go here http://www.wnselectrics.com
I found I needed to run a tap through the threads as they were a tiny bit snug, but apart from that no problems
Pattern Part No was 113974 made by Holger Christensen which is apparently a Bosch company http://www.hc-cargo.com/Default.aspx?ID=7&GroupID=MC/Starters&ProductID=113974
I have no involvement with either company blah blah
You can buy one made in china a copy of a valeo .These are listed on ebay Germany for about £57 all in and delivered via dhl to the uk paid with PP and with free return by dhl if you have a problem. Its about 1/2 the price of buying in the UK. I bought one and it turns a lm4 engine over quicker than the Bosch, it works ok looks ok and time will tell how good it is.I had thought about looking inside it when it arrived to see if the magnets had the clips on them as per later valeo’s but decided not too just in case i had to return it for any reason. There’s not much info on the web about there reliability but the pattern one’s for bmw 's don’t seem to be giving any problems .I’ve always got the bosch to put back on if needed. 
Mite there be a part number on yey starter Ralph…?
Don’t think there is .It’s bolted on the bike and with the sidecar also on it’s a bit difficult to see.But i will have another look later.When mine came it did have a sticker on with a number printed on it but i think this was the German ebay sellers number.The sellers ebay name is not on the invoice although i bought via ebay,he’s in Koblenz and he has a web site www. mi-autoteile.de if that’s any use.He still has them listed ,it may be easier to find him if you look via ebay Germany.He lists them on a number of listings for different models some times with different price’s all must be the same part. His listing photo only shows the starter from the drive end NOT a side view as most others do. I also think there are/must be a number of chinese makers of these if you look at the various photos some are painted differently .
UPDATE .Ebay’s sellers name is Autoersat2teile-koblenz He will come up on a ebay uk search if you put in guzzi starter also his listing will be in english. There is a sticker on the starter with D6RA21+ and another number starting with 400 can’t see the rest and 30035 .I can’t see anything else. Overall outwardly the look quality / finish wise is very good, what there like inside and the quality of the materials is unknown.I bought basicly to see what they were like, you can pay more than twice the price in the uk for a chinese one .Time will tell if they are any good. It’s a case of you pays your money and takes your chance.
Cheers Ralph…x
Updated above.
And thanks again…x
not sure if you can still get them, but valeo used to sell a body only with magnet installed with a better resin