Hey @GeordieG, I use EnjoyTaxiBangkok for my trips

https://www.enjoytaxibangkok.com/transferrates

It's 1700 baht from Bangkok to Pattaya. They can pick you up from Pattaya to go back to Bangkok but you'll need to let them know in advance. 

I've always found them reliable, their 'Big Taxi' transport is comfortable, and their drivers are friendly and don't drive like maniacs. 

In the last year I’ve used Nam’s taxis several times and it cost 1500 between Sukhumvit to Pattaya, and 1200 between Suvarnabhumi and Pattaya. I’m pretty sure that on one occasion the cost was slightly higher because they didn’t have a small car available.

Cheers @Denbosch1971, I've actually used them before and might again to head back to Sukhumvit from Pattaya. However I had a poor driver experience with them once where he was driving like he was in Mario Cart and I'd prefer a more comfortable 2hr ride after just landing! Aot have always been very professional and Nam's have a reputation for careful driving.

You can try to pre-book Orange taxi from Pattya. Last time (January last year) they brought me from Sukhumvit to Buakhao and charged me 2200 THB. So from Suvarnabhumi it can even be less   Communication with them is very easy via WhatsApp or Line. Booking via tablet PC is also possible. HOME - Taxi Pattaya Have a good one mate! 

I was looking at pre-booking AOT for my transfer to Pattaya on arrival and was suprised to see the price being quoted in excess of B3000. I've used them once previously to get to Pattaya and I don't remember it being over B2000. I thought I'd check to see if anyone else had noticed price increases with AOT, as to be honest both the app and website are terrible for booking and I wondered if it could be throwing me an unusual price. I sent an enquiry to Nam's taxi who have a much more reasonable rate and have lots of fans on the Pattaya forum, but I normally like the convenience of AOT. Not at that price though! Edit: just checked, I paid B2280 in October!