Witjout a spec it's hard to be sure but I imagine the HDI is a low noise design suitable for marginal signal areas like Southern Spain. If you are in the UK and not in the depths of Northern Scotland then a normal quad should be fine
Looking at the product on Amazon it just likes a company trying to profit from promoting as HD enabled when in fact they are most likely to be using the same branded LNB as the one you've purchased for £10. You'll probably find that the branded LNB you have purchased with the spirit level is either a WNC or Thomson, both good makes. Others include Zinwell and MTI.
Thanks for your help ian-d i was thinking along the same lines just wanted to be sure now i just need to get the plastic coating off (not a cap). Ill look it up here and find out how to this is a great site with alot of knowledge and usefull information