I’m in the UK, and have used D B Marine (website: dbmarine.com) ..of Cookham Bridge, Cookham on Thames, Berkshire SL6 9SN. Tel: 44(0)1628 526032 Fax: 44(0)1628 520564 Email: firstname.lastname@example.org ..for all my spares, such as replacement hoses, engine anodes, etc.
They weren’t able to supply a new oil cooler, but I think they supplied a used, but renovated 2nd-hand replacement cooler for me. Fast service, and they’ll send anything anywhere. They hold all sorts of spares for the Ford Lehman / Sabre engines.
But perhaps your best bet is simply to use Google and / or eBay – as you’re not in the UK – to find the supplier closest to you!
If you find yourself unable to secure a specific part in the EU/UK, I’d suggest at least checking with American Diesel (PH# 804-435-3107) over here in the USA. Brian Smith is quite helpful when diagnosing things too. Bomac Marine, is another potential US source.
On an aside, I usually check EBAY too. Always a little scary, but sometimes you can find spare parts from reputable vendors.