I had my 1200ESA shocks rebuilt by MCT in Stowmarket by mail order, the rear was leaking so was done first which then highlighted how soggy the front was. They had to press a rod bushing into my front shock and ream it to size as part of the rebuild. It transformed the bike.
Denz0 has a great reputation and does repairs by post. Whoever you use get both shocks done together. You won’t regret getting both shocks put back to ‘better than new’ for a massive change in feel. If the rear has gone, the front will be not far behind.