Vinyl can be great fun but good decks at low prices aren't always easy to find. I'm not sure of budget but the Sony PS-6750 is damn good and goes for £250 ish. You could always get a bargain if the seller lists as a buy it now and doesn't know what they are worth. A few of the old DIrect Drive Pioneer, Sony, Technics, JVC and Denon can be good. The Technics SL-1200 and 1210 are plentiful and you could get a bargain locally. Some of the Technics linear trackers go cheap and are decent too. Keep a look out for LAD turntables too. They often go sub £100 and are fitted with a very decent Jelco arm.

Good belt drives that can be had cheaply are the decks Rega made for NAD, Goldring and Akai. They are essentially slightly cheaper versions of the Rega Planar 2 but can often go for as little as £70-80 with a cartridge. You have a talent for securing bargains, so I reckon you'd probably snipe one for this sort of money.

As Chris says, it will be tough to find a headphone amp with a phono stage in. Probably better to pick up a decent amp that has a good phono stage and a headphone socket. Something like a NAD or Mission/Cyrus would fit the bill. Early NAD 3020 and 3130 are fun IMO and so are the early Cyrus one and Two. Failing that,my out can always buy a cheap phono stage from Project, NAD or Goldring for £20-35. Then you can buy any headphone amp you like.

Edit: Chris and I both assumed you already understand what a phono stage is and why you'd need one. Basically, the output from a turntable is very small compared to a tape deck or a CD player. It needs an extra boost and also some frequency equalisation in order to be be on a par with a tape deck or CD. Some integrated amps already have phono inputs which contain this extra gain and equalisation. Buy one of these and you're good to go. If you buy an amp or headphone amp without a dedicated phono stage, you will need to buy a separate one to boost and equalise the signal. It would plug between your turntable and amp.

There are two major types of phono cartridge too: Moving Magnet and Moving Coil. The latter are lower output and often tend to be more expensive. Some amps and phono stages will cater for both types of cartridge but some are Moving Magnet only. 

Oops, sorry if I missed that. That's a pretty nice deck if you have.

I'm not on Aes, but it seems blabbermouth has told you we chose the RP6!!!

I suspect a lot of people ask a question to which they already have the answer.
It's usually a matter of proving to yourself that you made the right choice, especially if for any reason you have doubts.

I drive my wife nuts whenever I've bought a new toy by spending ages afterwards looking around to see if I could have done better !

Buy an amp with a headphone socket. Save herself the headphone amp entirely.

I have a HFN/RR Headcase amp. I believe it was made by Moth Marketing