I wouldn't worry at all..the reason being that, in addition to what JZD has already said the various UK consumer legislation, esp the Sale & Supply to Consumer Regs 2002 give you various important rights. Much simplified the law says:
The shop keeper is liable and responsible to you, not the manf.
A manf.'s guarantee can give you added but not lesser rights than the law has set out, it is probably riddled with lots of ifs and buts.
The goods remained at the sellers risk until they were safely delivered to you. ( S20 Sale of Goods Act 1979 as amended by Sale & Supply of Goods to Consumer Regs. 2002. ) also see Unfair Contract Terms Act 1977, as amended .. " consumer guarantees .. where goods are sold .. with a consumer guarantee, the guarantee takes effect AT THE TIME the goods are delivered .. " ( words in capitals are my emphasis )
Their two years on your dishwasher is, I would argue less than your existing rights that you might be able to exercise if something goes wrong.
For the first six months if anything goes wrong the presumption in your favour is that the dealer has to prove the goods were not inherently faulty, it's called the reverse burden of proof. .. but !
Even after six months and even up to six years ( 5 in Scotland ) you have certain rights such as repair, replacement, a % of the purchase price back, etc. all on a principle that some goods will obviously have and be expected to have a longer life than others.
If you do need to exercise your various rights eg. repair, replacement etc the dealer has to carry them out without undue delay so they can't leave you without a dishwasher for months on end playing you along.
Their 'small print' therefore can't take away anything from you that the law has given
I suggest you speak to the dealer gently reminding them of the points above, and any sign of them stringing you along visit you local council trading standards/ consumer protection dept. and they'll help/