I followed a similar path to you having played dobro for a number of years before buying my first pedal steel about a year ago. I bought a
Stage One from Doug Earnest in the US and I have been very happy with it. It gets many favourable reviews on the US Steel Guitar Forum from pros as well as beginners. Many pros like it because it is relatively light and use it as a tour guitar for that reason.
Doug sells them for $949, which would be around £600, but you would need to add shipping and then the import taxes on top of that which would bring it close (or slightly over) your budget. I can't remember how much the tax was on mine, but it would be at least 20% on the cost of the guitar and the shipping. Doug is great to deal with as well.
I will probably upgrade to a 'pro' guitar at some point, but I'm struggling to find reasons to do so other than gear acquisition syndrome (GAS). The Stage One plays well, stays in tune and is easy to learn. As far as I can tell, the only major drawback is that it is not possible to change the setup of the three pedals and four knee levers to anything other than the Emmons copedent. Many players in the UK seem to go with the Day setup, but most instructional material assumes the Emmons setup. Doug is about to release a new guitar, possibly called the Stage Two, which will allow changes to the pedals and knee levers, but I'm not sure when that will happen.
The other option for you would be to buy a good secondhand pro level steel. I'm sure others here can advise you on what to look for in that area. Having read many many posts about what to buy as a beginner, I got a strong sense that most other 'starter' guitars were to be avoided.
I hope that helps.
Chris