I guess it depends on your budget and what your trying to achieve..........you need to ask yourself why those are only 25 quid, I wonder what their tensile strength is compared to the standard Nissan or whiteline bolts.
After nigh on a decade of modifying these cars and like a few others spending far to much time and money on the subject, the one constant theme of advice running through these forums is if you want it to last and be reliable, it's just not worth doing things on the cheap. That's not to say that all expensive products are all quality products and worth there extreme prices and not all cheap parts are rubbish. Lets just say that with the time and inclination it would be quite easy to search the archives of the OC and the modifiers write up a shopping list of quality parts to suit your budget.
If set correctly and not played with constantly Whiteline camber bolts can be fine for a road car, I most definitely wouldn't want to use them on a track car though, it's also quite common for them to loose there adjustment due to the suspension banging about on our amazing roads. In my opinion adjustable top mounts if you can afford them would be the the most reliable option.