Dog walker advice

Hello we are thinking of going away and will leave Harley with my mum. We are looking into getting a dog walker to attend my mum's in the day to take Harley out. My mum is partially sighted and has limited vision she also suffers with asthma so taking harley may get a bit much. The dog walker I've seen walks next doors dog and all the reviews and pictured look good on the Facebook page. She offers a free assessment for all her dogs my only worry is he won't like it as he can be picky with certain dogs. Offlead with his ball he ignores 99% of other dogs and has great recall, without his ball he gets very distracted and wants to chase dogs. He can be sometimes picky other with intact males, collies and small terriers. On lead he does not cope well with dogs running upto him and does lunge and growl.
If it works out in the assessment we will use her see how it goes then think about him going more regular for socialisation.
do you guys think this is a good idea or not? My only worry is that he can be unpredictable but most of the time can get along with dogs.

Would it be with asking if she could do a private walk with Harley and either keep him on lead like a street walk or see if their are private fields she can take him too.

I'd definitely meet her and see what she says. It's a terrible worry leaving then with others. When we go on holiday my mum and dad have Misty and I forbid them taking her to the park. I'm sure they would just let her off lead like they used to with their Lab!

have a chat with the dog walker you'll know within yourself whether they would be able to handle harley or not my fiancee is totally blind and mias marvellous with him she even showed him a kerb one day . id see what qualifications the dog walker has perhaps you could go with harley and the dog walker a few times to see how she would handle certain situations . harley may react totally different as he would with you as you know know his habits. i went away for a day once i got my friend to look after mia she went to a shop never tied mia up she didnt know how and mia waited on her coming out!i was stunned when my friend told me good luck.xx