Have you tried equestrianclearance.com? - Luck of the draw whether they have your size though. Weatherbeeta do a landa combo for around that money I think but i'm not sure of the filling weight. Or you could always just get a 100g liner for under a non-fill rug?
I got a rug off ebay for £30 (+ p&p), by the brand name of protuff. Not sure what they will have atm, but for the price, best rug I have ever bought!
I got an Ultima turnout from Ebay with full neck, it's meant to be 300gm fill but I'd be doubtful if it was that warm compared to my WB Arion or Fal Pro of about the same fill but it was only £12.50 and it fits really well so I'm happy!
Try cybercheckout.co.uk I've just bought a lightweight Horseware Amigo for £29.99 - colours are a bit dodgy, but if you don't mind your horse in pink or brown...!
i got a great rug from www.premierequineinternational.com
great prices, theres a sale on. I got the 450g turnout with neck and it is lovely. quick service too.
Ditto ^^^Really pleased with my PEI, think I would of if I'd paid £150 let alone £60! Parkers now a trend setter as few other liverys have brought them.