Some generations of Celicas had the 7AFE engine - who\'s exhaust manifold is very close, dimensionally, to a 4AFE engine. May not be a 100% bolt on swap (actual length is different, but flange bolt pattern matches), but has been done before. The Corollas 7AFE and 4AFE exhaust manifolds are interchangeable in a similar manner.
I didn\'t list any vendors - as I don\'t know which ones you are able to select from in the UK, that\'s why I mentioned aftermarket header from the 4A series of engine (4AGE, 4AFE) would be potential choices for your modifications. The OEM and aftermarket 4AGE exhaust manifolds are a popular mod to the 4AF engines - some modification is necessary to make the flange area fit.
Keep in mind that you will not see miraclous improvements in performance. Even here in the US, even with quality I/H/E (intake/header/exhaust) bolt on mods on the 4AFE - dyno plots have shown only 3-7HP gain. The major impediment being the cylinder head design and the OEM engine computer air/fuel and timing maps.
As for brands - lots of knock-offs out there, so be wary. Most find themselves through channels like eBay or similar. OBX is near infamous of being one of those knock-offs - sometimes you\'ll get a decent one, other times, you\'ll find shoddy workmanship (cracked welds, wrong bolt pattern, etc.)
Pacesetter is the only one that I know of specifically for a 6th gen Corolla. Option Racing and Matrix are two others that I know of, off the top of my head. There are quite a few others, sourced from the Philippines and Australia/NSW regions - that you might have better access than what we have here in the US.
2002 Corolla S, Silverstream, 1.8L 1ZZ-FE (VVT-i)
2003 Matrix XRS, Cosmic Blue, 1.8L 2ZZ-GE (VVTL-i) - RIP
2009 Matrix XRS, Blue Streak, 2.4L 2AZ-FE (VVT-i)