Firstly don't feel like you are the only one to have faced this. I certainly didnt feel too confident at going outside my comfort zone when I first got my PPL. The good thing is that you are recognising this and seeking guidance. Rather than heading off gunho into class A airspace !
Here's a few things that I would suggest :
1. try and buddy up with someone else in a similar situation or even better more experienced but looking for company or to share costs. 2 brains and 4 eyeballs are much better.
2. hire an instructor at Stapleford to sit in the RHS. I think you can log the time as P1S ? They can do as much or as little as you want but if nothing else will be there to confirm all is ok. I did this as I had never landed away at a large airport. Went to Newcastle. It wasnt what I expected. Never been anywhere like that again by choice.
3. Spend time looking at the charts for the area. Plan some flights in your head and imagine where you might go and what you might do.
4. Slowly expand your circle of confidence. Im not familar with Stapleford but a quick glance at the charts suggests that its fairly free of controlled airspace to the east. Why not plan a flight out and back. Once your happy with that you can stretch the elastic a bit further. Again once you comfortable with that maybe try a 3 leg cross country. After that you might want to land away.
5. Looks like the LAM VOR is near Stapleford. Use it to track away and back to the airport. Will help ensure you dont get lost.
6. Alternatively. Pay me loads of money to come down south, put me up in a 5* hotel and I'll happily sit beside you for 40 hours.
Above all, dont be afraid to ask for help. I'll bet you just about everyone who flies has been where you are at present. The good thing is that you have asked the question whereas many others would be too afraid. Moreover if you can get over this hump then within a few hours your confidence levels should increase considerably and you will thoroughly enjoy the rest of your 40 hours.