You need to check all the specs @vman , especially the inverter. £4600 sounds low compared to recent prices I’ve seen and the inverter being the control unit is key to monitoring and getting the most from the installation. 
If you are even thinking about the possibility of batteries in the future, the inverter should be capable of supporting them otherwise you will need a new inverter at that time as well. 

Panel costs vary quite a bit, depends on where they are made, cheap is not always less expensive in the long term. The inverter, it is imperative to get the best if you are thinking of installing batteries, Car charger or other add ons.  Tread carefully and do your research, there are a lot of people out there selling on price alone.