FTB Multiplier single income 4.5 or 5x?

Hi All,

So i'm looking into mortgages, the online calculators are suggesting for my £41k salary (includes a bonus) I can get around the £200k mark, which is roughly 5x.

I rang L&C today and they suggested 4.5x is pretty much what they would expect, and not to get an Offer/AIP until i've had an offer accepted...

My issue therefore is, what should I be looking for house price wise as I don't know what i'm going to get and don't want to run a load of credit checks for no reason to find out?

Properties I like (surrey, walk to work so no car outgoings etc) are in the £230-235k bracket.
with the 4.5x plus £40k i've got ~£225k
with the 5x plus £40k i've got ~£245k

I've got the £40k deposit plus a bit for legals and some free furniture heading my way, my fixed outgoings are roughly £50 a month with no debt.

My plan is to rent out 2-3 rooms and then overpay the mortgage (3 rooms after tax will give me ~1000 which means no mortgage payments) so while I wouldn't be over stretching myself the bank presumably wouldn't take this into account.

Any advice, or other FTB experience on the multiples likely?

Cheers,