From giantshark.co.uk
XYH35-36 1050kv 25A Brushless Outrunner
EZRUN-25A-L-SL Brushless ESC for 1/18 Car I use these car ESC's because they have an additional mode called rock crawler which gives instant reverse. The water-cooled Sea versions only have a double click reverse mode which is slower and doesn't always happen. Useless for emergency stops.
The EZRUN esc's come with instructions to program using the transmitter. if you can get a EZRUn Program Card it makes setup very quick. Not in stock at present
Using this in a 36" Atlantic Challenger weighing approx 7lbs 50X prop and 7.2 NiMh 3300mA pack 20A car fuse. Peak current around 18A. Goes very well. if you want to go for higher voltage pack to get more speed then keep a check on the current. Start with a smaller prop. I keep a set of plastic X props from 35X to 55X. SHG Models have them at£1 each. The ESC will trip if it gets too hot, but shouldn't be relied on to save the Esc from overload
Wattmeters to show watts amps peak amps etc are around £20 and is very useful if you are trying different props too.

If you want to go to a high power motor then N3542/04-KV1250 Outrunner Brushless Motor with EZ-RUN 35A w/ Reverse program Brushless ESC or the 60A one is a next step
Hope this will be of use. Any questions, I'll try to help.

HI Alan, yes I agree and I'm on a budget, so I'd like to hear from anyone who has tried or where I should go for an alternative.

Had a look at that Dave, looks OK, if a bit expensive. You may have to run on 3 cells and be careful not to over prop and burn something out.

Let us know how you get on

Alan

Not without a motor to go with it Dave 😀
The Mtronik Hydra 50 is a 50 amp speed controller
with reverse, and at £77 pound is an expensive one.
perhaps you should look for a motor first, maybe one with a wattage of between 800 to a 1000 watts, then you will be able to work out the amps it will draw and choose a speed controller to suit.
But I am no expert, it's just the way I go about it.

Alan