One of the companies who is tendering for the job to rebuild the site has said:
The old links are not in a common rule so we will have to make links redirect manually so this work will take a lot of time (you said that you have more than 1000 products).
Couple of questions:
Would this be accurate? How long would it take in hours approx to redirect 1100 urls to the new sites url's? Are there any other options open to me that wont be detrimental to my standing in Google? If you were in my position, what would you do about these redirects?
Thank you very much in advance for any assistance and advice you can offer.
I think it may well be a manual process, unless there are key similarities between your new and old urls.
For that number of redirects it could be days as opposed to hours!
It might be an idea to find your pages that are ranked and actualy receiving traffic and redirect those as a prioroty, If you have pages that simply arent listed then the redirect may not be worth while. This would reduce the number of redirects.
How long has the original cart been active? Weeks? Months? Years? If the latter two you'll probably want to redirect. If the first, or even the second, perhaps just making the move and starting over is a better way to go... hit for a bit but strong thereafter.