Oh I would have done it for you if you were north west! I reckon you could find someone who would do it cheaply if you are willing to use someone relatively recently trained. I would say though that you will be wearing your face and hair all day and looking at the photos for years, so it's worth paying for someone really really good to do them for you - I don't get why hair and makeup isn't top of the priority list for many people, but then I am a total makeup addict and it's a bit of a hobby for me (I have some hair and makeup qualifications and when I'm back up and running after DD2 who arrived last week I'll be pursuing this further).
I think the makeup counter ladies are hit and miss - some of them are just sales girls who have very limited makeup training, others are trained artists who are just earning some regular money. In London they might be more likely to be proper makeup artists looking to just earn regular funds whilst also doing freelance makeup work given that there's lots of training institutions and work there. You could try contacting the main makeup schools to ask for a recommendation for a recent graduate - some of them have jobs boards and you could say, 'I can afford to pay £x for wedding hair and makeup and I have a pro photographer whose images you can use in your portfolio' and ask them to put it on the board for you. Greasepaint, London Muse, Academy of Freelance Makeup, Jodie Kidd makeup school etc are all in London (and there are dozens of others) so just email or call them and ask if they advertise jobs to students and graduates. Many will be happy to do you a deal for portfolio shots.
For the make-up.. consider going to a shop that has a make up counter (benefit, max factor, MAC etc)... and they will do a face of makeup for you... then maybe buy the powder and lipgloss to touch up during the day.
Work it into your budget, keep an eye out on Groupon, LivingSocial, Wowcher etc. they often have make over/ make up lesson type deals very cheaply. O r you could go to a MAC counter in you local dept. store and get a tutorial and some make up to do it yourself, I think you only have to spend £30 there.
Could you ask someone for it as a wedding present? I got mine done and it was calculated as part of the wedding budget. There is way to getting it don't cheaper. If they come to your house or hotel they may charge more than you going to the salon. Ask around for recommendations. Do you have any guests coming that is great with hair or make up? Having a trial run will cost money but I thought was worth it too. Congratulations!
My hair sounds the same as yours, either straightened or left to dry so it's curly. I've just saved and got vouchers for a local salon for my birthday to have y hair, nails and make up done. I do wear make up but only a bit of mascara and blusher. I just know I couldn't do t how I wanted it on the day so I think I need a pro to do it!