Here you go. Not sure if its the same one the obove person is referring to but this one should fit i think. Provide the seller your reg and they should be able to confirm.
https://www.ebay.co.uk/itm/116255552147?_nkw=GS450H+radiator&epid=755707114&itmmeta=01J6D6WEWHEQRNMJYASTMFWEZX&hash=item1b115ef293:g:RZkAAOSwgKxlcybK&itmprp=enc%3AAQAJAAAA8HoV3kP08IDx%2BKZ9MfhVJKlxdFjyztwTZEgO8b%2FV8SxsK%2BO9GT808akouzv2nu5R51ffh5nRhNMtw2v%2FZcB7QExwimPweM2i%2BhpBESrYpACWwC5BlPwd7iXhlceEbpNbZ%2BbLvqNKilYEocsK4x3h8A579fc4g1%2B3YSL%2BDGzoXrnLJh3OShy00uTlVG%2FaSX9K6IASeL3ubs9254jf4Mq4UIElSkI3hYrnlHKu1G%2BFogDMVfHM6N--2n4qnLs59TsAhnhbOMind6T69rE8sR9XlrrsicBrKa61WvjdyETlCKpKJeasFQXXay%2BbjTlxrtqKgA%3D%3D|tkp%3ABk9SR67u8aazZA
This one might fit too and is cheaper
