Over 20yrs ago I went to my local Numatic agent. The sort of place that supplies some of the shops and spare parts. For £100 he made me up from odd bits a metal cylinder unit with auto switching head. He included 5m hose and the supplementary "hospital grade" fine material filter. I use mdf and hardwoods, and have renovated my 3 houses on a back to brick basis. The best test for me has always been a total lack of smell from the unit when vacuming up plaster and mdf dust. I have run anything up to my 1850w Elu router through the unit. I have NEVER needed to use a bag filter. I am still using that original supplementary filter provided. After 15 yrs the switch unit started playing up, so I replaced the part. Last summer I upgraded the motor from the original 900w to a 1200w.
If I was buying again I would definitely buy a a Numatic, but from Axminster, as its cheaper. The one you want is the Numatic ARXP470 Power Tool Vacuum Extractor. I know its out of your price band, so its a matter of watching the small adds, ebay etc.
Out of interest, or possibly not, we have also run a Numatic Henry in the house since we got married, Oct 1985. I would have no hesitation in buying another of product off them.
Colin