I'm afraid I can't help with the name of a tutor, but I just wanted to ask if you've considered DIY?
The business of finding a good tutor who really understands the 11+ in your area seemed so difficult/ secretive to me that I decided to DIY and on the whole have really enjoyed it. Where I am (Exeter/ East Devon) some children I know have had up to 3 tutors
(one each for English/ Maths /VR) but have still not made it through the test. A mum I know sent her child to a tutor for nearly a year but about a month before the test she realised that VR was included and the tutor had not been teaching it until that point!! Her DC did not qualify. DD's class teacher said that for many years she has watched Yr 6 children go through the 11+ and she believes the school (Colyton for us) is pretty good at selecting the right children, with the odd blip.
I don't want to scare you, but I don't think the tutor scene is as developed in Devon as, say, Bucks, so unless you have a recommendation from a friend or know the tutor has definitely been successful for the school you are applying for and fully understands the Devon 11+ tests, I would tread very carefully, particularly for VR, and perhaps consider DIY. Patricia's tips for VR are great; we didn't start in earnest until Easter of Yr 5 (but made sure times tables were up to scratch before then) and did nothing over the Summer hols. Maths I bought the CGP revision guide and went through each section to check DD understood it and did GL papers and Bond papers. When I got stuck, there was always someone on here I could ask to help out with the answer (Yoyo, Guest55 for Maths, Patricia, Sally-Anne for VR and many others- thanks guys!). English I left to the school TBH, as DD is confident at English anyway. From September we spent around 3 hours a week on 11+ prep. Approx 1.5 hours per week from Easter to July.
Of course, I don't know whether it has worked for my DD until March....!