I'd source from John Lewis or Argos - it will then have a 2 year no hassle warranty (John Lewis). Both sellers will provide good customer service and you wont have the hassle of arguing with a seller if your camera is dead on arrival.
While reliable - DSLR can easily be damaged during manufacture, you've no idea if you are buying a b-grade + if that site is shipping from HK then you've VAT and Duty on top, if it gets picked up during shipping.
Avoid - starter cameras, bridge cameras etc - no better than an iPhone and wont let your learn 'proper' photography. That 4000D has a DIGIC 4+ processor and while its old, it was the processor that launched the original 7D, which was camera of choice for sports photographers and semi pros when it came out.