Might be able to get a 105 bottle of Cask strength for £40 if you’re lucky.
Tullibardine 500 would be similar and a little rarer for the same/less money
Caol Ila is good but the cheap stuff is a bit subtle, nicely balanced though – not as full-on as other light-but-peaty whiskies like Ardbeg.
Jura Superstition will be well within your budget and is great value – Talisker without the pepper.
Ben Riach 16 is an excellent speyside for little outlay if you fancy trying a lighter malt