Sorry for the double post but I was unable to add this to the original post above.
Cheap usually means cheap. F5 is OK for backup or bedroom box but experience tells me to always go for a box that runs Enigma2 minimum and which, most importantly, has wide and up-to-date image support. There are loads of good choices out there now and many of the Chinese clones are a bargain if you get the right one.
£50 for a box is not realistic and you should not expect much for that price. Add a bit more and buy something 2nd hand or best of all buy something decent to begin with. Better to pay £200 or so for something that lasts than pay £50 or so every few months for something that either breaks or quickly becomes obsolete even unsupported.
£50 boxes rarely, if ever, get any image updates or support or enhancements. You are basically stuck with what you buy. Like Samsung, when a manufacturer has new features then rather than firmware update existing kit they release a new model and expect us stupid punters to buy new kit. They call this business. Some might call it theft.