Hi there I am a "Ham" too - call sign G7RTI. I have only Yaesu equipment, FT817 & 840. The 840 was bought 2nd hand about 6 years ago. Still works fine. I use it a lot on 10w and it's not modified.
Below from the T&C
http://www.watersandstanton.co.uk/
Guarantee New products supplied by us are guaranteed for 12 months, except Yaesu and Icom radios, which are both guaranteed for 24 months. Used products are guaranteed for 3 months. Parts and labour are both covered under the guarantee. This runs concurrently with any manufacturer's express warranty that may apply. The said warranty will be rendered void if the internal workings have been tampered with beyond that sanctioned by the manufacturers or ourselves. The warranty excludes wear and tear, external or internal damage caused through misuse or accident. We can offer extended warranties for up to 5 years at competetive prices. Please contact the sales department for more information. All information given about the warranty is in addition to the customer's statutory rights and those rights are unaffected.