Ok, I have a climbing wall and we offer free wifi to the customers – at the moment that is running via a BT Business hub 3 that our office comouters also connect to the internet with.
We have a web based POS system and the internet can grind to a halt on busy evenings when loads of people are connected to the wifi .

OK, I would like to do 2 things :
1, Partition off the customers wifi from our office network for security (can I put it in the dmz ? or does this just partition from the internet side ?)
2, Throttle the bandwidth for the customers wifi network so the office system stays working !

I know I can limit the number of connection via limiting the numbers of DHCP leases, but i dont want to do this as it means people coming up to the counter asking if there are problems.

Help please, and it needs to be fairly low cost as if I go back with an expensive option the other directors will veto it !

Assuming your existing one can’t do it, buy a separate wireless access point and hook it up to your router. Look for features of “guest portal” and the ability to set bandwidth limits.

Make the new one your customer wifi on a separate name/key, keep the BT hub for your business stuff.

This is pretty basic functionality these days, I like Ubiquiti Unifi UAPs which are good and pretty cheap but there’s lots of vendors.

Awesome I shall have a look

A cheap wireless router running DD-WRT gives you the ability to set up a WiFi hotspot. I use a TP-Link TL-WR1043ND at home, works well with DD-WRT and is about £40.

http://www.dd-wrt.com/site/support/router-database

How To Set Up Your Own Free Wifi Hotspot With DD-WRT

Cool, more reading up !