Daisy chaining introduces two issues:
1) Potential overloading of the socket due to too many devices on the extensions. (You know once you or your missus see a spare plug it wont stay spare for long. Think Hoover, Hairdryer, curling tongs, beer fridge, etc)
2) Potential for electrical noise from the additional "break-point" between cables.
Number 1 is obviously more of a health and safety issue and as long as you are sensible, should not really be an issue, Number 2 is more subjective and I do not want to spark the age old mains cable debate in this thread, but mention it more from the point of view that extension cables are typically not as snug fitting as wall sockets. Turn out the lights and pull out a plug from a typical extension cable and you will see what I mean (please dont sue me for any "arc-eye" you may experience).
All that said, if you are filtering out the noise at the final end, then you should be ok.
I would agree with looking into getting a longer cable fitted (by a qualified electrician) as a longer term bet.