For 7 days, do you think £1000 would be enough to cover food drink and fun?
Depends how fussy you are and your preferences (LT vs ST, etc). £1000 is about 39,000B so about 5,500B per day.
My rates are years old but I'm a fussy short-timer so maybe the calculation is still about right. Perhaps you'll need a bit more.
Bangkok
Daytime: BJ bar, say 1000B at a usual place like Lolitas or Kasalong including a drink or tip. (I'd skip the drink. Waste of time)
Evening: Gogo girl, not sure exact barfine these days. 700B? 2000B S/T for a looker in demand.
Nightcap: Freelancer, perhaps 1000-1500 s/t.
That's 5,200B on girls alone. Drink in bars is 100B per time but I wouldn't treat it like the UK anyway alcohol-wise. There are more interesting things in Thai bars.
Food is cheap. You could eat well at somewhere like Foodland for a few hundred baht a day.
Pattaya's worse for BJ bars, better for freelancers. Perhaps cheaper with less quality in the gogos but more young guys on stag dos and Chinese tourgroups.
Personally I'd forget massage places because you don't get to see the goods beforehand and I prefer girls with perfect bodies (no signs of childbirth or scarring). Also, I find they're just not as good with services. E.g. They'll tend to offer cbjs not bbbjs as standard with gogo girls and freelancers.