There are a number of Chinese inverters have come on to the market, some cheap as chips. Problem is lack of provenance and track record.
The good news is there has been some market reaction to this. Happily my favourite inverter has had a significant price reduction. You can get Eltek 3.6 for £500 and the 2.9 for £429. Try Andy at Sibert or Ecolution who are now main agent.
These are high efficiency inverters with galvanic separation and a built in web server. Warranty is now 5 years rather than 10, but can be extended for less than £100.
Customer feedback very positive. Low light performance impressive. One report from an overcast day in mid February where system started to generate at 8.00am.