My sister got one recently from Wren Kitchens and the quality was very good. They fitted it themselves though. This page lists the other major brands for kitchen suites.
With Wren - ensure you go through the design completely (including checking all the colours and doors match) BEFORE signing on the dotted line. It took three reviews before our doors matched colours and we had all the right units. Don't get pressured or let them off the hook when you're getting the design and bill of materials. Wren don't provide after sales support. Wren have a reputation for being butts for "this is what you've ordered as contracted".
Also check all your delivered doors and components inside the 24 hour delivery period. You will get all the components for the higher ranges prebuilt without the doors on. We had a couple of bruised door corners. You will get the entire kitchen in one delivery and it will be assembled (if it's the higher ranges) - that takes space.. so plan the logistics

The kitchen is decent quality. I'm happy with the functionality and the look. Although we have a couple of marks on the doors over it's lifetime so far, the paint you will NOT be able to get. Also replacement doors are almost impossible to get (we have an additional door for a high traffic area just in case).
We took the entire work top as the thick breakfast bar style to raise it up (I'm 6'4 and the wide isn't too short) as I find normal worktops and the position of the sink makes my back ache (tall person accessibility!).
We had our own fitter. That was an experience as the fitter was a bit of a bodge-it merchant. So get an experienced independent person with experience of Wren fitting. The wren fitter refused some of the modifications we had planned (we have a back of one of the cupboards modified to accommodate a pipe).
So I have a love/hate relationship with Wren. Good design, decent quality but the organisation and attitudes sucks money nuts.
My parents have a German brand (I can't remember the brand name) - it's better quality than wren and the connected fitters (local to them) did a top quality installation.
Also have a think about what you need in the kitchen before you go into the design.. Wren were happy to start with double ovens etc, inbuilt x/y etc however for us we went for a Bosch series 8 oven but then had standalone spaces for our appliances (which so happen to all be Bosch already! Not that I'm a Bosch fanboy :/).
Our kitchen company definitely warned us about appliance delays.