Dont know the kitchenaid, but I know the little gaggias quite well. If it has gaggia components, you should be able to get good results.
If you are moving from pressurised to non-pressurised baskets as I suspect, there will be some relearning involved. You will need to grind finer and probably tamp harder. What sort of grinder do yoy have? What beans are you using?
For servicing, 9bar are often recommended for service and if they cant help, will know someone who can.
For bits and pieces like tampers, milk jugs, thermometers etc., coffee-a-roma are just down the road from you in camberwell.
Best upgrade would be to install a PID controller, but it would ruin the look. You may want to research temperature surfing.