I am currently running A32 Maxima Caliper brackets, with B15 Sentra SE-R rear discs from a car with the factory Brembo brakes option. They are 4x114.3, and you must redrill to 4x100, only takes 10 minutes.
This setup is a complete bolt on and gives you a much bigger rotor that still fits under 15" wheels, and you can still use the GTi-R rear brake pads. It may be a bit difficult for you guys in the UK to get the USDM Sentra rotors though. Rock auto will deliver international if you ask. Here's the link to what you need.
These are the caliper brackets that can be had from Rockauto.com for $16.48 each, and they're interchangable between left and right, just order 2.
http://www.cardone.com/Products/Product-Detail?productId=141506&p=rock&jsn=391&jsn=391
and here are the rotors you need that must be redrilled.
https://www.rockauto.com/en/moreinfo.php?pk=3870219&cc=1430919&jsn=604
Rock auto has several different brands and types to chose from, depending on how much money you want to spend, these are just the cheapest ones I found. Just make sure to get the ones that say "With Brembo brake package"