We recently visited a number of homes in Wallasey for my mum (though as it turned out her condition deteriorated and she ended up needing nursing care rather than residential). Of the ones we visited, we were most impressed with Sandstones, on Penkett Road. It was modern, clean and well staffed, rooms were a good size with an en-suite in each, and we were made very welcome. We spoke with a few of the residents and they were all very happy.
A good website is Carehome.co.uk, which lists all types of care home, with facilities, contact info and a link to the CQC report for each individual home. Residential homes in the Wirral are at http://www.carehome.co.uk/care_search_results.cfm/searchunitary/Wirral/searchchtype/carehomeonly
Agree with the above - always visit unannounced. If they are reluctant to let you in, be suspicious (though it may be best to avoid meal times, as it is hard for the staff to give their attention to a visitor when they also have 30+ residents to get meals organised for, and it can be disruptive for the residents. Draw up a list of questions which are appropriate to your neighbour, so you make sure you ask the same questions everywhere you visit. We were given a booklet which had a list of possible questions, we found many were not appropriate so reduced it down to our own list.
Good luck finding somewhere, it's a difficult decision to have to make.
eta - if you can, visit on a weekday, as the matron/manager is often not there at weekends. There were a few places where the person who showed us round couldn't answer all our questions and had to get the matron to call us on the Monday.