Thanks for your reply, had just about given up on this one.
I'm on 4.1.2 stock md3 and using WPA2 encryption. Don't think it matters though because I've had these problems from the get go, on stock ROM when just bought and on various Wifi encryptions (random browser timeouts, no Wifi connection drop though...). Can't really see a pattern, sometimes my wifi will work flawlessly, other times it just refuses...
Was wondering wether others had a similar issue. If you've got any ideas, do please let me know. Tbanks again!