£3,969 - The Wellington Academy
£4,050 - Thomas Adams School
£4,100 - Beechen Cliff School
£4,100 - Burford School
£4,135 - Dallam School
£4,440 - Old Swinford Hospital
£4,460 - Brymore Academy
£4,668 - Liverpool College
£4,833 - Richard Huish College
£4,838 - Reading School
£4,982 - Keswick School
£5,000 - Wymondham College
£5,087 - Ripon Grammar School
£5,094 - Haberdashers' Adams
£5,100 - Sexeys
£5,115 - Lancaster Royal Grammar School
£5,450 - Cranbrook School
£5,580 - The Royal School Wolverhampton
£5,625 - St George's School
£5,719 - Hockerill Anglo-European College
£5,790 - Holyport College
£5,799 - Steyning Grammar School
£6,315 - Peter Symonds College (catchment secondary for the kids in the Falkland Islands)
£6,500 - Royal Alexandra and Albert School
£7,110 - Duke of York's Royal Military School
£7,865 - Gordon's
So cheapest is The Wellington Academy at just under £4k a term, and most expensive is Gordon's at almost £8k a term. A lot have higher fees for 6th form and I didn't look at if some include some extras etc.